Highlights

• Firefox 154 went out today! Lots of goodies in there for our users, including support for NVIDIA GeForce NOW
• The new 2 week release cycle is now in effect. This means that Firefox 155 is slated to hit release on September 1st!
  • You can follow along at https://whattrainisitnow.com/
• As part of the Nova redesign, a “Use Linux system theme” checkbox is being shown on Linux builds for the about:addons theme picker, which will make Firefox’s Nova UI use the colours of the system theme.
• Thanks to Simon Rosen for adding a new playback speed control to the PiP player. The feature can be enabled by flipping the pref media.videocontrols.picture-in-picture.playback-speed.enabled.

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

Volunteers that fixed more than one bug

• Benoit
• Chris Vander Linden
• Fede
• japandi
• Lukáš Lipinský
• Nirmal Advani
• Ruhollah Majdoddin
• Sameem [:sameembaba]
• Sebastian Zartner [:sebo]
• Zyphrenn

New contributors (🌟 = first patch)

• Aditi: Increase the maximum number of PDF.js preferences
• Fede:
  • more than six thumbnails needed when Ctrl+Tab is used
  • Clicking “delete group” on group context menu in tab groups list doesn’t dismiss toolbar panel
  • Tab group context menu actions fail when right-clicking the label or icon of a tab groups list row
• Giulio B: frameId is wrong in webRequest events triggered via importScripts
• 🌟 Gopalarathnam Venkatesan: Fix incorrect ‘this’ in the Sync add-on install error handler
• 🌟 Kevin Gosse: nsDataObj::QueryGetData in Firefox returns E_FAIL for formats it doesn’t carry, instead of DV_E_FORMATETC per the COM contract
• 🌟 mikey gough: Remove three unused devtools.debugger.file-search-* preferences
• 🌟 Nathan Leuz: Remove unused legacy preference browser.translation.neverForLanguages
• 🌟 Priyanshu[:0xanshu]: “Forget About This Site” dialog is cut off
• 🌟 K: Disable breakpoints shortcut
• 🌟 Shawn Zivontsis: Reorder moz_origins composite unique index to UNIQUE(host, prefix)
• 🌟 Simon Rosen: Suggestion: Add speed button for Youtube in picture-in-picture(PiP) modals
• tanvi.manku: unnecessary scrollbars in edit dialogs for payments and addresses
• Zyphrenn:
  • browser.tabs.groups.enabled should disable drag-n-drop
  • “Tab group suggestions” AI control setting still visible when browser.tabs.groups.enabled is false

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• As part of Nova about:addons work:
  • Replaced the “more themes” button in the themes list view footer with a promo element when Nova is enabled – Bug 2057200
  • Removed the testing XPI base url pref from ThemesList.sys.mjs – Bug 2053220
  • Fixed a mismatch between the popup panel border radius applied by Nova and the border radius applied to the document.body of the WebExtensions popup page loaded into it – Bug 2057844
  • Moved new strings added as part of the about:addons Nova restyling out of the locales preview – Bug 2052034
• As part of legacy telemetry cleanups for the Add-ons related telemetry, migrated addons-search-detection telemetry off the legacy telemetry mirroring path, now collected only through Glean – Bug 2055606

WebExtensions Framework

• Fixed a series of intermittent and CI-reliability test failures across the WebExtensions browser-chrome test suite – Bug 1575369 / Bug 1697626 / Bug 1699341 / Bug 1974953 / Bug 2015004 / Bug 2030542 / Bug 2062186 / Bug 2062187 / Bug 2062189 / Bug 2062191 / Bug 2062193
  • Thanks to Florian Quèze for applying his work on an LLM-based system for investigating intermittent tests to investigating and fixing intermittents and perma failures across the WebExtensions test suite.

DevTools

• Ruhollah Majdoddin fixed issues in the Storage panel to make sure we’re only showing relevant cookies (and their values) for the debugged tab (#1856645, #2060029, #2061166) and also did some cleanup in this area (#2061348)
• sevenwithawp added a keyboard shortcut (Ctrl+Alt+B, Cmd+Alt+B on Mac) to disable/enable breakpoints (#1642578)
• Hubert Boma Manilla (:bomsy) continues his work to display stylesheets in the Debugger (#2051029, #2051264)
  • Preference: devtools.debugger.features.stylesheets-in-debugger
• Nicolas Chevobbe [:nchevobbe] added support for ::picker() rules in pseudo element section (#2042839)
  • Used by customizable select (MDN)
  • Preference: dom.select.customizable_select.enabled

• Nicolas Chevobbe [:nchevobbe] made CSS explainers work for substitution functions (var(), attr() and env()) (#2041622)
  • Preference: devtools.inspector.css-explainers

• Julian Descottes [:jdescottes] fixed an accessibility bug in about:debugging where error message where not announced (#2056332)

WebDriver

• Sameem added the cleanup logic for subscriptions when a browsing context is destroyed.
• Nirmal Advani updated the Actions API to fire the dblclick event when performing a double-click while holding down the Ctrl key on non-macOS platforms.
• Khalid AlHaddad updated the webdriver bidi moz:debugging module to stop using enterNestedEventLoop which can avoid conflicts with the regular DevTools’ debugger.
• Alexandra Borovova fixed the “browsingContext.reload” command to not fail for frames.

New Tab Page

• Big ticket items:
  • Did a trainhop last week to help with the remote layouts effort
  • Doing another trainhop this week to make some spacing optimizations, deploying tomorrow if all goes well
  • We will be experimenting with some more layout variations over the next few months
    • Example:

• We’ve migrated a bunch of our unit tests to Jest/RTL from the deprecated Mocha / Karma framework we’ve historically used.
• Joel added a WebNotifications badge to Top Sites on the New Tab Page which surfaces per-origin unread web-notification state directly on TopSites tiles by rendering a compact badge in the activity-stream/TopSites component—users can now glance at NTP tiles to see which sites have pending web notifications without changing navigation or site state (affects desktop and mobile NTP Top Sites UI). This is something we plan on experimenting with later this year.
• Similarly, Joel added a TopSites hover card with notifications which expands the to show per-site notification items and actions on hover or long-press, enabling users to read and dismiss notifications from the NTP itself rather than opening each site.
• Hanna Alemu fixed the focus outline for the “Learn how we protect your data” link in NEWTAB_PERSONALIZATION_MESSAGE, replacing the blue non-rounded ring with the standard rounded focus style via CSS so keyboard and assistive users get a consistent, discoverable focus indicator.
• Maxx Crawford added logic to show different tip messages throughout the day/week on the New Tab Page in the upcoming privacy widget, implementing time-of-day/day-of-week selection in the tip renderer so users receive context-varying tips rather than a static message, which affects the tip surface and supports time-targeted experiments.
• Irene Ni removed the New Tab daily briefing slice from the New Tab Page, so users will no longer see the daily-briefing card on new tabs and related New Tab slice prefs/registrations were cleaned up.
• Jack Brown migrated the New Tab ContextMenu/LinkMenu implementation to the panel-list component, so right-click menus and link context behavior on the New Tab now use panel-list rendering (affects keyboard navigation, theming, and menu perf).
• Irene Ni removed a root-level <hr> selector from the Weather forecast widget SCSS that leaked global divider styles into the New Tab Page layout, restoring correct dividers and preventing spacing/layout regressions on about:newtab.
• Irene Ni enabled the remote-settings-driven sections layout in Nightly, flipping the remote-settings/sections layout so Nightly users receive Discovery Stream section composition from Remote Settings.
• Irene Ni automated the New Tab Page locales update for train-hop to ensure locale bundles are refreshed on train deploys so users see corrected translations and no longer encounter stale labels after a hop.
• Reem Hamoui fixed the Crossword widget double-counting and removed broad “interaction” user_actions so telemetry and UX-triggered actions reflect a single user event and analytics driven by user_action are no longer inflated.
• Dre fixed the “Show more widgets” visibility by adjusting the widget container overflow/visibility logic so the Show more control is reliably revealed on constrained viewports, restoring widget discoverability.
• Joel fixed newtab.closed and newtab.sections_impression firing unexpectedly on the New Tab Page by gating event emission on section visibility and tab lifecycle, which stops spurious impression and close telemetry pings and improves the accuracy of NTP impression/close counts for affected users.
• Joel added a topsite display customization event to newtab ping, updating the New Tab ping schema so user topsite layout and appearance changes are emitted as topsite.display_customization events, enabling reliable capture of pin/remove/resize/customization actions in Telemetry.
• Nina Pypchenko [:nina-py] added widgets.stocks.interaction and flip it on user actions so explicit click/tap interactions with the Stocks widget now generate widgets.stocks.interaction events, improving engagement capture for the Stocks surface.
• Nina Pypchenko [:nina-py] migrated the Stocks widget telemetry to the shared useWidgetTelemetry hook, standardizing how the Stocks widget emits metrics and ping fields to match other widgets, which reduces missing/duplicate events and makes per-widget telemetry consistent across platforms.
• Irene Ni created an initial JSON dump of Remote Settings sections layouts for cold startup to prepopulate New Tab Page sections on first launch and reduce layout flash or missing tiles.
• Nina Pypchenko [:nina-py] added a persistent “New” badge to the Stocks widget until first user interaction, which improves discoverability of the Stocks card and is cleared on the user’s first click/tap.
• Maxx Crawford implemented a side-by-side content layout variant for the New Tab Page feed, which introduces a new responsive layout option that changes feed column behavior and visual density on wider viewports.
• Scott Downe added support for five-column content feed layouts, which enables denser content grids for large displays by updating grid logic and responsive breakpoints and affects NTP rendering on wide screens.
• Dre added a “Celebrations” UI state to the Privacy Widget, which surfaces milestone/celebratory visuals and transient animations in the Privacy Widget when triggers are satisfied.
• Irene Ni updated the New Tab topsite context menu button to respect prefers-reduced-motion via CSS/media-query changes, so users with reduce-motion enabled no longer see the button’s motion/animation.
• Scott Downe expanded New Tab’s list of region and locales for content support, updating the New Tab content selection config and region→locale mappings so more users in newly-added locales receive localized tiles and recommendations on the New Tab Page.
• Irene Ni fixed the New Shortcut / Edit Shortcut prompt background being transparent with the Newtab addon installed, restoring CSS/background opacity for the edit UI so shortcut editing is readable across themes and addon combinations.
• Maxx Crawford added a dedicated trainhopConfig.widgetPrivacy payload for the Privacy widget feature, introducing a per-trainhop config payload in Discovery Stream so Privacy widget rollouts and toggles can be controlled without code deploys.
• Maxx Crawford added a layout management panel in Discovery Stream Admin, giving editors an admin UI to modify New Tab/stream layouts (reduces manual config edits and speeds layout experiments).
• Dre reduced the Privacy Widget celebration sparkles on the New Tab Page in Privacy Widget Celebration: Reduce the Sparkles by lowering particle counts and throttling animation cadence in the widget’s CSS/JS animation code, reducing visual noise and a small amount of GPU/animation work for users during the celebration without changing privacy settings.
• Maxx Crawford restored the “Change size” context menu item for the side-by-side experimental New Tab layout so users with the side-by-side exp layout enabled regain the resize control in widget context menus.
• Maxx Crawford stopped the sports widget from rendering regardless of the pref so unwanted sports content no longer appears on New Tab when the pref should prevent it.

Picture-in-Picture

• Thanks to Lukáš Lipinský for adding live event caption support for ceskatelevize.cz!
• Thanks to Mike Conley for fixing play / pause issues with the PiP player on Udemy.

Search and Urlbar

• Nova: continued work on the Nova redesign, focusing on CSS fixes, tab group and container styling, and tab/address bar polish. Efforts are underway to ensure the UI integrates correctly with platform themes and high-contrast modes.
• IPC Urlbar / Multi-Context Address Bar (MCAB) on New Tab: Significant progress has been made on the IPC Urlbar implementation. The CI variant is now live and upgraded to Tier 2, allowing for better bug detection. Currently focused on making content modules content-process-safe and preparing for new tab search bar integration. Here’s moz-urlbar rendering something on about:newtab for the first time:

• Post-MVP work continues on refining the new search bar that can be added to the toolbar.
  • Let Tab land on the search input rather than the search button, behind a Nightly-only pref
• Google address bar messaging experiment relaunched.
• Search & Suggest Telemetry: Development is ongoing for search term telemetry, specifically regarding fetching results from Merino for online suggestions. Also preparing to retire legacy telemetry for certain search service metrics.

• Favicon & Places:
  • Bookmarks for Google Apps use the root icon instead of the newly released one
  • CopyFavicon should only copy across same origin pages
  • Favicons are not affected by a hard refresh
  • Bookmarks/history locked error at startup despite no external process holding places.sqlite
• Also trim www from URLs, behind pref

Highlights

• Want some Kit? Check out the store!
  • 
• Sebastian Zartner [:sebo] added a panel to expose @media emulation (#1692434) and provided a way to emulate @media (prefers-reduced-motion: reduce) (#1477920)
  • 
• More theme controls have been added to the New Tab customization panel:
  • 
• Improved Picture-in-Picture caption support from some volunteer contributors
  • Thanks to Lukáš Lipinský for adding caption support to Česká televize!
  • Thanks to kernp25 for adding caption support to ardmediathek.de!

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

Volunteers that fixed more than one bug

• :Vincent
• japandi
• Nirmal Advani
• Sebastian Zartner [:sebo]
• tanvi.manku

New contributors (🌟 = first patch)

• Aditi: Increase the maximum number of PDF.js preferences
• 🌟 Anil Verman: [Docs] Trigger listeners doc is seriously out of date
• Fede: more than six thumbnails needed when Ctrl+Tab is used
• Giulio B: frameId is wrong in webRequest events triggered via importScripts
• 🌟 Luiz Henrique Vieira: Remove dead CSS rule .alltabs-item[selected=”true”] 
• 🌟 Devin Rousso: `emulation.setLocaleOverride` does not override `Accept-Language` header for in `Worker` for `fetch` and `WebSocket`
• 🌟 muhammad shaikh: Profile delete page heading should enclose profile name in quotes
• 🌟 Kevin Gosse: nsDataObj::QueryGetData in Firefox returns E_FAIL for formats it doesn’t carry, instead of DV_E_FORMATETC per the COM contract
• Lukáš Lipinský: Česká televize captions do not display in the Picture-in-Picture window
• 🌟 mikey gough: Remove three unused devtools.debugger.file-search-* preferences
• 🌟 Nathan Leuz: Remove unused legacy preference browser.translation.neverForLanguages
• 🌟 Shawn Zivontsis: Reorder moz_origins composite unique index to UNIQUE(host, prefix)
• tanvi.manku:
  • Remove or update metrics expiring at the end of Firefox 154: pwmgr.doorhanger_submitted_* before Gecko switches to version 155 on 2026-07-20
  • unnecessary scrollbars in edit dialogs for payments and addresses
• 🌟 Tim McNulty: Remove always-true clause from NS_ASSERTION in nsNavBookmarks::AdjustIndices (Coverity CID 1274453)

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• As part of Nova about:addons work:
  • Introduced a shared localization module for built-in and curated AMO-hosted theme names, and updated the corresponding about:addons theme test to expect the new “Default” theme name shown when Nova is enabled – Bug 2055936 / Bug 2058235
  • Added a message bar to the about:addons themes picker to surface AMO-hosted Nova theme download and install failures instead of failing silently – Bug 2054548

WebExtensions Framework

• Fixed a startup race where an extension’s restored dynamic content scripts could be missing from the parent WebExtensionPolicy due to stale shared data – Bug 2058719

WebExtension APIs

• Fixed publicSuffix.isKnownSuffix() to reject invalid domain-name characters, including wildcard suffixes, that could previously be matched as a known public suffix – Bug 2059819
• Fixed the frameId reported by webRequest events for requests made from workers, including importScripts()-loaded scripts, which were previously attributed to the wrong frame – Bug 2048884
  • Thanks to Giulio B for the fix to webRequest frameId attribution for worker requests.

DevTools

• Benoit made it possible to display JSON Lines (JSONL/NDJSON) documents in the JSON Viewer (#2055774)
  • 
• Leo McArdle [:leo] continues his quest to add MDN icons next links to MDN (#2049610, #2050159)
• Julian Descottes [:jdescottes] vastly improved DevTools screenshot performance (by up to 35%) (#2056716)
• Hubert Boma Manilla (:bomsy) fixed keyboard navigation for about:debugging (#2050797)
• Julian Descottes [:jdescottes] fixed a bug that was preventing to show error messages in about:debugging (#2058021)
• Nicolas Chevobbe [:nchevobbe] made ::checkmark pseudo element visible in the Inspector (#2009909)
  • Used by customizable select (MDN)
  • Preference: dom.select.customizable_select.enabled
  • 

WebDriver

• Nirmal Advani cleaned up our codebase by removing the executeSoon helper, which was just a thin wrapper on top of Services.tm.dispatchToMainThread().
• Sameem removed support for the “contexts” argument in the “session.unsubscribe” command. From now on, clients can unsubscribe only by event names or subscription ids.
• John Schanck added support for validating if an authentication id is stored in the Virtual Authenticator Database.
• Alexandra Borovova disabled the download panel to prevent the loss of the focus of the current document when a download begins.

Fluent

• Here are utilities for measuring localization coverage at runtime

Lint, Docs and Workflow

• Sylvestre has converted all our in-tree documents to be Markdown instead of reStructuredText.
• Standard8 adjusted the source doc upload task, that runs on code review, to report failures into phabricator, rather than having a generic error message.
• Standard8 made it so that test-manifest-toml issues for out-of-order entries should show up in phabricator more often.
• https://arewemozsrcyet.com/ continues to head (mostly) in the right direction.

New Tab Page

• HNT Eng had a work week last week. Did a lot of prep for big cleanups (Nova, Widget cleanup post WCW)
  • Also worked on ways to automate trainhops / make them easier to deploy
• Jack Brown updated newtabTrainhopAddon to allow co-enrollment and prioritize the highest version number, which ensures the New Tab Page picks the newest addon build when multiple enrollments overlap and prevents older experiment variants from replacing newer installs.
• Fred Chasen fixed AccuWeather sponsored text overlapping the “Tell us what you think” link by adjusting medium weather card CSS (z-index and pointer-events), restoring hover and click behavior for the feedback link on affected New Tab Page cards.
• Mike Kaply fixed wallpaper uploads failing when the wallpaper list can’t be queried from remote settings by adding a remote‑settings query fallback/local cache and defensive error handling so users can upload custom wallpapers during remote‑settings outages or timeouts.
• japandi added the widgets.clocks.interaction pref and wired interaction tracking so World Clocks now emits telemetry/events for taps and opens (pref registration + tracker hooks), enabling accurate UX metrics without changing visible UI behavior.
• Maxx Crawford prevented the weather widget from activating without user opt‑in by gating activation on the opt‑in pref and updating the onboarding flow, so weather and related location/telemetry remain disabled by default until explicit user consent.
• Irene Ni made the New Tab client request layouts from remote-settings so NTP layouts and remote-config-driven content now update on load instead of remaining stale; this fixes cases where layout changes pushed via the remote-settings service (layouts collection) weren’t applied, improving consistency on desktop and Android clients that rely on remote layouts.
• Nirmal Advani removed three unused activity-stream preferences (discoverystream.thumbsUpDown.*) from prefs and related code paths, reducing prefs surface area and avoiding confusion in about:config/telemetry without changing user-visible behavior.
• Mike Conley fixed ExternalComponentWrapper to forward “live” properties like isIntersecting from MessageWrapper, restoring correct IntersectionObserver-driven behavior (visibility-based lazy-load and impression tracking) for remote components in the New Tab Page and discovery streams that relied on isIntersecting for render/telemetry triggers.
• Irene Ni standardized New Tab widgets and sections header spacing (standardize spacing) to remove misaligned tiles and reduce visual jitter when resizing or toggling sections in the New Tab Page.
• Mike Conley removed version-153 train-hop compatibility shims for the World Cup newtab logo variations (remove compatibility shims), an internal cleanup that prevents legacy logo-selection fallbacks from influencing current logo variations.
• Maxx Crawford exposed available browser themes to New Tab and added apply/install actions (expose and apply themes), allowing users to install or immediately apply themes from the New Tab surface via ThemeManager/Theme API hooks.
• Maxx Crawford added New Tab Customize Panel browser theme selection strings (add theme selection strings) so the new theme-selection UI is localized and displays correct labels across locales.
• Maxx Crawford added a full browser theme selection sub-panel to the New Tab Customize Panel (theme selection sub-panel) to let users browse, preview, and pick themes directly inside the New Tab customization flow.
• Scott Downe fixed Custom newtab wallpapers flash / blink some seconds after loading newtab by ensuring the custom wallpaper is painted only after image data is ready, which removes the multi-second visual flash on about:newtab for users with custom backgrounds and improves perceived stability during initial new-tab load.
• Maxx Crawford exposed trainhopConfig values in Discovery Stream Admin tooling, giving operators direct access to trainhop routing/weight values from the admin UI/API so content trains and experiment routing can be adjusted without code deploys—this has no immediate end-user UI change but reduces time-to-rollout for Discovery Stream content changes.
• Dre fixed Newtab custom wallpapers flash when selecting from picture of the day widget by deferring the wallpaper swap until the selected Picture of the Day is decoded and ready, which prevents the transient blank/flash users saw when changing wallpapers via the widget and makes wallpaper selection feel instantaneous and stable.
• Maxx Crawford used the POTD thumbnailUrl image for the widget background (instead of the high-res image), which reduces bandwidth, memory footprint, and New Tab Page widget load latency for users who see the Picture‑of‑the‑Day widget.
• Kyle Jones added MAC support to TopSitesFeed when fetching tiles from MARS, which enforces authenticated tile retrieval and reduces missing/401 tile failures for users relying on MARS‑served Top Sites tiles.

Performance Tools (aka Firefox Profiler)

• Bug 2050028 – Enable the Gecko profiler by default with low-overhead features when running mochitests landed, which means mochitest failures now upload profiles by default:
  • 
  • https://tests.firefox.dev/try.html can give you a prompt to ask an AI agent to look at the profile for you using profiler-cli:
    • 

Search and Urlbar

• Dao and Moritz continue work on MCAB working on making the address bar’s contents to be content-process-safe and preparing to allow cross-process IPC for the address bar.
• Mike Kaply fixed hidden actions still visible in Quick Actions mode.
• Daisuke and Drew continued work on supporting Nova on the address bar and search bar components.
• Caleb continued work to use array–binding for places sql queries, to improve performance.

Highlights

• Starting in Firefox 154, we’ve added a new capability for changing the default browser icon for Windows (Windows-only, for now, and not MSIX / Store installs) in about:settings#appearance!

• • Notice any bugs? File them here!
• Hubert Boma Manilla continued his work to handle CSS files in the Debugger (#2036376, #2037041). The feature can now be enabled from the Settings panel (#2051876)

• The Picture-in-Picture WebAPI is now available, starting with release version Firefox 153!
  • This does not replace the built-in Picture-in-Picture mechanism, and is in fact powered by it.

Friends of the Firefox team

Resolved bugs (excluding employees)

Volunteers that fixed more than one bug

• japandi

New contributors (🌟 = first patch)

• 🌟 Luiz Henrique Vieira helped remove some dead CSS from our tabbrowser code!

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• As part of Project Nova work:
  • Added moz-promo cards to the about:addons extensions list recommendations footer and empty state, and updated the openAmoInTab helper to support a custom UTM content value – Bug 2043615 / Bug 2050880
  • Introduced the building blocks for the Nova Themes Picker in about:addons: a shared Firefox Themes list source of truth, a light/dark/device theme-mode switcher, a reusable theme-preview webcomponent, and Nova-styled theme previews – Bug 2051554 / Bug 2051559 / Bug 2051564 / Bug 2051573
  • Updated the Extensions panel empty state illustration and toolbar item icon for Project Nova – Bug 2030715
    • Thanks to Michael Hynson for driving this.
• Removed the legacy AddonManager Glean metrics used for mirroring legacy telemetry events, along with the corresponding legacy telemetry test checks – Bug 1923949 / Bug 1981822
  • Thanks to Chris H-C for collaborating with us on this.
• Fixed themes installed through the distribution mechanism not fetching their AMO metadata, which was resulting in distribution installed themes left without a preview image in about:addons – Bug 1917279
  • Thanks to Mike Kaply for the fix to the distribution themes metadata handling.
• Fixed amContentHandler to verify that a system triggeringPrincipal genuinely originated from the parent process, a regression introduced in Firefox 153 and fixed in Firefox 154 (with a beta 153 uplift requested) – Bug 2048964

WebExtensions Framework

• Fixed a startup performance regression by avoiding an NSS-initializing crypto.getRandomValues() call during extension startup, a regression introduced in Firefox 153 and fixed in Firefox 154 (with a beta 153 uplift requested) – Bug 2050882
• Enabled tier 3 TypeScript typecheck linting for the extensions framework code – Bug 2050124
• Implemented the WebExtensions manifest sandbox key, letting extensions keep using string-based code execution in unprivileged sandboxed extension documents – Bug 1685123
  • Thanks to Robin for the implementation of the manifest sandbox support.

WebExtension APIs

• Enabled storage.local database auto-reset on detected corrupted IndexedDB storage on all channels, starting in Firefox 154 – Bug 1992973
• Simplified registerTraceableChannel to make it synchronous again, removing the delay before blocking webRequest listeners can register a traceable channel – Bug 2044518
• Restored the contextualIdentities iconUrl container icons to their intrinsic 32×32 size, fixing a regression introduced earlier in the Firefox 154 cycle – Bug 2048599
  • Thanks to Andrea Marchesini for the fix to the contextualIdentities container icons.
• Fixed the MV2 userScripts API failing with an Xrays TypedArray access error due to a missing isWebExtensionContentScript flag – Bug 2054083
  • Thanks to erosman for the fix to the MV2 userScripts API.

DevTools

• Emilio Cobos Álvarez fixed the Inspector highlighters for SVG documents (#1850539)
• Andreas Farre made the Session History table header clickable to navigate the content page to given entry (#2018878)
• Sylvestre Ledru added Browser and Content filter to the Browser Toolbox Console and the Browser Console (#2048893)
• Adel Fatkhutdinov adapted the about:debugging Performance dialog for Nova (#2049348, #2053817)

• Nicolas Chevobbe about:debugging is now using moz-page-nav for its left sidebar (#2048544), thanks to Mark making it possible to disable collapsing that occurs on narrow screen (#2050907)
  • (not all items were migrated to moz-page-nav-button though, see #2050746 for remaining work)
• Alexandre Poirot made it possible to control the request and response body size limit from the Settings panel (#2040892)

• Alexandre Poirot added a notification when DevTools are open and the user navigate to a file:// document to promote Local Mode (#2044464), and added documentation for the feature (#2045987)

• Nicolas Chevobbe improved Inspector performance for elements with lots of Rules (reported bug was causing a crash on Penpot) (#2034445)
• Alexandre Poirot made the Ruler to remain visible after reloading the page (#1247553)
• Nicolas Chevobbe made the DevTools splitter keyboard accessible (#2015949)
• Nicolas Chevobbe fixed pretty printing in Debugger for sources using Regex with the v flag (#2053574)

WebDriver

• Devin Rousso enhanced the emulation.setLocaleOverride command to allow overriding the Accept-Language header for fetch and WebSocket requests in Workers.
• Nazım Can Altınova created the moz:profiler module (mozilla-only!), allowing clients to control the Firefox Profiler from WebDriver BiDi.
• Julian Descottes fixed a bug in geckodriver which prevented connecting to a non-rooted device.
• Alexandra Borovova implemented the “browsingContext.startScreencast” and “browsingContext.stopScreencast” commands, which will record a browsing context and save the result as a video file.
• Alexandra Borovova added download id to “browsingContext.downloadWillBegin” and “browsingContext.downloadEnd” events” to make it easier to identify which events belong to the same download.
• Henrik Skupin fixed a bug in WebDriver BiDi where same-document navigations or loading error pages in frames caused the browsingContext.navigate command to return prematurely.
• Henrik Skupin released geckodriver 0.37.1, including a fix for Android. See the release page for details.

Credential Management

• The new Rust-based storage mechanism for logins has been enabled by default, starting in Firefox 154. This component is an application-services component that can be shared with iOS and Android.

Migration Improvements

• We recently updated the Passwords import instructions for Safari to be up-to-date with macOS Sequoia and up.

New Tab Page

• That’s a wrap for the World Cup! We’re powering down the Sports widget today.
  • Some folks might see a survey about the Sports widget, to get feedback from the wild on whether or not it provided any user value (Telemetry points to “yes”, but it’s good to get qual data too)
  • We’re replacing it with some new widgets. If you’re in an English-speaking region, you will probably see it replaced with a Daily Crossword widget. Otherwise, it’ll be replaced with a Picture of the Day widget.
• Sections have rolled out to 100% in France! We’re now doing 10% Sections experiments in Spain, Italy, Austria, Switzerland and Belgium.
• Shout out to volunteer Sameeksha who added an accessible name to the Task list widget ••• button, adding an aria-label/accessible-name so NVDA/VoiceOver announce the control and keyboard navigation/activation works correctly on New Tab.
• Joel added WebNotifications to the newtab state, allowing New Tab widgets to observe and reflect WebNotification events (affects the notification-driven widget lifecycle and UI state updates).
• Reem Hamoui adjusted the New-Tab Widgets 3-dot menu layout to vertically center menu entries inside the hover-granted colorful stripe, removing visual misalignment and small hit-area offsets on touch and pointer inputs.
• Dre implemented the show less/show more transition animation for New Tab expand/collapse, smoothing layout shifts with a CSS transition to reduce perceived jank during widget list changes.
• Scott Downe fixed New Tab Page drag-and-drop so widgets no longer jump or keep moving during drags (2049472).
• Reem Hamoui rendered the Daily Crossword in a sandboxed iframe to isolate its scripts/CSP on the New Tab Page (2049489).
• Reem Hamoui added the Crossword option to about:preferences and wired the New Tab Page crossword widget into prefs (2050340), so users can enable or disable the crossword via the standard Preferences UI rather than about:config.
• Dre set up the Picture of the Day boilerplate, including prefs and basic New Tab UI components (2050969), which exposes a configurable PoD surface for users to opt into and customize.
• Dre added a dismiss control and persisted dismissal state to the daily photo UI (2050972), allowing users to remove the current picture from their New Tab and avoid immediate reappearance.
• Dre added a “set as wallpaper” action and hooked it into New Tab wallpaper storage/prefs (2050973), enabling users to promote a PoD image to their custom New Tab wallpaper persistently.
• Dre connected the Picture of the day widget to the Merino endpoint to set the background of the widget to the current picture (2050976). He also added telemetry for the Picture of the day widget on the New Tab Page to capture impressions and clicks for usage analysis (2050977).
• Nina Pypchenko [:nina-py] added a small size variant for the Focus Timer widget in Nova so the timer can render compactly in narrow/new tab layouts and reduce vertical space usage (2051179).
• Maxx Crawford created a DevTools ‘controls’ area on the New Tab Page to enable and configure the widget, exposing toggles and settings that let developers and experimenters flip the widget without changing prefs, which reduces friction when reproducing NTP widget behaviors during debugging and testing.
• Irene Ni switched the New Tab ‘inferred personalization’ checkbox to the platform moz-checkbox control, restoring native checkbox semantics (role/keyboard focus/visual state) so users toggling inferred personalization see consistent a11y behavior and platform rendering across Windows/macOS/Linux.
• Scott Downe fixed an intermittent visual reload/flicker of sponsored tiles and the Add Shortcut button when pinning/unpinning shortcuts, preventing momentary tile DOM reflows and layout thrash that caused perceived data loss or longer perceived latency during shortcut edits.
• Scott Downe ensured custom image URLs persist on manually added Top Site tiles after edit, so users’ uploaded or external thumbnails no longer revert to the site’s homepage preview when saving edits and their custom thumbnails are correctly cached and displayed.
• Dre introduced two variants of the World Cup widget survey message, changing the copy delivered in the widget to support an A/B/message-variant experiment and altering what users see when the World Cup widget surfaces survey prompts on their New Tab Page.
• Nina Pypchenko [:nina-py] introduced a default state for Medium and Large Stocks widget sizes on the New Tab Page to surface placeholder content and avoid blank tiles when the Stocks feed is empty or slow to load.
• Nina Pypchenko [:nina-py] added an error state to the Stocks widget on the New Tab Page to show an explicit failure UI when quote fetches or network requests fail, reducing user confusion.
• Alexandre Hanot migrated AdsFeed to fetch New Tab ads through the MozAdsClient, changing the ad retrieval path (AdsFeed -> MozAdsClient) which affects ads loading behavior and telemetry for users who see New Tab Page ads.
• Irene Ni fixed the New Tab add-pin flow that was creating extra rows when grouped pins was off by changing the insertion logic to append into the existing grid, which eliminates unexpected row creation and layout shifts for users managing many pins (2053251).
• Scott Downe updated New Tab section rendering to hide cards that don’t fill their row by adjusting layout logic/CSS, removing orphaned placeholders and reducing blank space on narrow viewports or low-item sections for a cleaner grid appearance (2053264).
• Reem Hamoui added a context menu to the Crossword widget using a postMessage integration between the iframe and parent page, enabling right-click actions (copy/hint/theme) and making the embedded crossword more interactive and accessible to users who rely on context menus (2053311).
• Reem Hamoui added a visible “New” badge plus interaction handlers and state tracking to the Crossword widget on the New Tab Page to improve discoverability and make tapping/clicking behave reliably when launching puzzles (2053667).
• Irene Ni removed unused Add Shortcut OMC artifacts from the New Tab Page (2053843); this is a cleanup of obsolete assets/templates and has no direct runtime user impact.
• Maxx Crawford added author and license attribution to the Picture of the Day widget (2053933); this surfaces photographer credit and license metadata on the New Tab Page for users who want provenance information.
• Maxx Crawford applied UX refinements to the Picture of the Day widget (2054109); users will see improved layout, spacing, and touch targets in the POTD area for clearer interactions.
• Maxx Crawford added a pref and trainhopConfig gate to toggle the POTD “Set as wallpaper” feature (2054111); rollout and availability of the wallpaper action are now controllable via pref and remote trainhopConfig.
• Maxx Crawford added a dedicated trainhopConfig.widgetPictureOfTheDay payload for POTD feature config (bug 2054112) so the New Tab Page train-hop widget can be controlled server-side — this delivers image URLs, attribution and display params remotely which lets us enable/disable POTD per cohort without ship-side changes and reduces rollout latency for users who see the Picture‑of‑the‑Day widget.
• Irene Ni updated the Shortcuts Add/Edit dialog for Nova (bug 2054175) to improve the add/edit UX on the New Tab Shortcuts surface — the patch adjusts dialog layout and controls, tightens validation and accessibility labels, and reduces accidental duplicate/invalid shortcut creation so users editing shortcuts have a more reliable, faster flow.
• Maxx Crawford fixed the Daily crossword widget content overflowing and clipping past the bottom container boundary by adjusting the crossword widget’s layout/CSS (container height calculations and overflow/overflow-anchor rules) on the New Tab Page, restoring full visibility of clues and controls across responsive breakpoints.
• Maxx Crawford fixed Related articles not opening on click by repairing the related-articles component’s click handling and event delegation (anchor href/target behavior and JS listener) on the New Tab Page so article tiles now reliably open on click for users.
• Maxx Crawford added a “New” badge and interactions to the Picture of the Day widget, implementing an isNew flag, local state/localStorage handling, ARIA label updates and click behavior so users can immediately see and act on newly added images.
• Maxx Crawford updated the initial order of the Picture of the day widget by changing the PoD component’s initial ordering/priority algorithm so first-run and default NTP surfaces surface curated/high-priority images first.
• Maxx Crawford migrated Crossword widget strings from Fluent back to inline markup to fix localization/formatting regressions in the crossword UI and ensure consistent rendering of labels and controls across locales.
• Irene Ni migrated the New Tab Widgets expand button to moz-button which standardizes the expand/collapse control on the New Tab Page widgets area, fixing inconsistent styling and keyboard/click handling so users now get consistent visuals and improved accessibility across platforms.
• Reem Hamoui added a dedicated trainhopConfig.widgetCrossword payload for Crossword feature config which isolates crossword rollout flags and content settings from other trainhop payloads, allowing targeted remote-config changes and safer A/B testing of the crossword widget without impacting unrelated New Tab features.
• Maxx Crawford fixed the Daily crossword widget being blank after closing and reopening the browser by ensuring widget state is correctly initialized/persisted on startup (New Tab Page widget lifecycle), so users now reliably see the daily puzzle after a restart instead of an empty frame.
• Reem Hamoui fixed Daily crossword completed puzzle and show clues are displayed in medium sized widget, restoring completed-puzzle rendering and clue visibility in the New Tab Page medium widget (widget template/CSS).
• Maxx Crawford updated Discovery Stream Admin buttons to use moz-button components, replacing custom controls with moz-button to standardize admin UI styling and focus behavior.
• Maxx Crawford added per-widget feature toggles and pref reset buttons to Discovery Stream Admin, enabling admins to toggle individual widgets and reset prefs without code deploys — changes here can alter what users see when toggled.
• Maxx Crawford migrated Discovery Stream Admin unit tests to jest, moving tests to Jest for faster developer feedback and more consistent test tooling.
• Maxx Crawford enforced Fail jest tests that emit console.error messages, making tests fail on console.error to catch regressions earlier and improve content quality before release.
• Kyle Jones populated MozAdsRequestOptions flags from adsBackendConfig in AdsFeed on the New Tab Page, changing ad request parameters that may alter which ads or personalization users see.
• Mike Conley removed the version 145 train-hop shim for the PrivacyFeed getTodayStats guard, simplifying guard logic in the New Tab Page with no direct user-visible change.

Search and Urlbar

Search

• Mandy fixed the “New” label incorrectly appearing for user-installed third party search engines that override application-provided engines (2053710).
• Standard8 fixed search engine telemetry notifications and private browsing search engine defaults (2053129, 1792669).

Suggest

• Adw added header_text support for AMP (AdMarketPlace) suggestions (2053626).

Nova

• Adw continued working on Nova with visual improvements across the address bar, search UI, icons, spacing, hover states, and accessibility (2019160, 2050821, 2053381, 2055109, 2053652, 2054784, 2055353, 2053927, 2053332, 2050366, 2053038).
• Daisuke improved the legacy search bar for Nova and fixed several Nova UI issues (2053934, 2050759, 2054304, 2046300, 2045993).

Address Bar

• Dharma improved Unified Search Button with search engine icons and a modernized result menu (2052741, 2039292).
• James continued work on adaptive autofill improvements (2013362, 2053891, 2050379).
• Dao and Mortiz continue multi-context address bar work (MCAB) (2054328, 2054207, 2054168, 2054110, 2054070, 2054066, 2051435, 2055474, 2054801, 2052555).

Places & Bookmarks

• Mak fixed several favicon and Places issues, including bookmark/history fixes (418144, 2055488, 2053482, 2052799, 2050378).
• Caleb improved Places performance by batching bookmark lookups and modernizing bookmark APIs (2042098, 2042099, 2042087, 2042097)

Storybook/Reusable Components/Acorn Design System

• Nova stuff
• Theme Picker for HNT, OMC and Profiles
• [mconley] There’s a new vertical variant for visual picker. Thanks for the reviews, hjones!

This past May, we shared our vision for the future of Firefox. Starting today, you can try out the next design evolution of Firefox in Nightly.

It’s still Firefox, now with a more cohesive look and feel across tabs, menus, panels, and other browser surfaces. You’ll notice softer tab shapes, a warmer color palette, updated icons, and – after hearing from many of you – the return of Compact Mode and new theme options to make Firefox your own.

Many of you have already spotted pieces of the new design in Nightly over the past few months. Now they’re coming together into one complete  experience.

You’ll continue to see updates over the coming weeks as we polish the new Firefox design before it reaches Firefox users more broadly later this year. As you browse, we’re especially interested in any visual or functional issues you encounter.

Keep an eye out for things like:

• Icons, spacing, and alignment
• Themes and personalization
• Different window sizes and display scaling
• Keyboard navigation
• Screen readers and other accessibility features
• Different languages and layouts

Found a bug?

If something doesn’t look or behave as expected, please file a bug in Bugzilla.

When possible, include:

• Steps to reproduce the issue
• Screenshots or screen recordings
• Your operating system and Nightly version

If you have broader thoughts or questions about your experience, join the discussion on Mozilla Connect.

Thanks for using Nightly and helping us improve Firefox. Every bug report helps us identify issues and continue refining the new Firefox design before it reaches Firefox users more broadly later this year.

Highlights

• Dao added a new Eyedropper quick action! Check it out by typing “color” or “eyedropper” in the URL bar (Bug 1803575) on Nightly.

• Henrik Skupin released geckodriver 0.37.0, which includes support for several new APIs and various bug fixes. See the release page for details.
• Starting from Firefox 153, access to local file: URLs is being restricted by default.
  • Extensions now require an explicit “Access local files on your computer” permission, separate from broad host permissions, that users must grant.
  • Extensions can call the extension.isAllowedFileSchemeAccess() API to determine whether they have been granted access to file: URLs (Bug 2034168).

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

Volunteers that fixed more than one bug

• :Vincent
• Chris Vander Linden
• DrSeed
• Khalid AlHaddad
• Sam Johnson

New contributors (🌟 = first patch)

• Francis :mckenfra: tld service for webextensions
• any1here: about:preferences#privacy is broken with MOZ_DATA_REPORTING false
• pullmana8: Fix protocol/Actor.js to throw an Error instead of an Actor
• RAN1: Firefox Crashes on Quit When Running Two Browsers With Separate Profiles

Project Updates

Accessibility

• Morgan added a new accessibility-specific, front-end review skill to mozilla central! 🎉 You can read about it, and learn how to use it in the accessibility review source docs.

Add-ons / Web Extensions

Addon Manager & about:addons

• Migrated addon-page-header and addon-card action buttons to the reusable moz-button web component as part of the ongoing Nova restyling of about:addons – Bug 2042200 / Bug 2042204
• Extended moz-page-nav-button with a forwarded title property to fix an accessibility issue where the component lacked a label in collapsed state; Landed in Firefox 153, and uplifted to Firefox 152 for about:settings which was already riding the 152 release train – Bug 2040971
• Fixed a shutdown-timing bug where a pending GMP update-check timer could fire after XPCOMShutdownThreads started, causing a pref write assertion; Fixed in Firefox 153 – Bug 2043803

WebExtensions Framework

• Fixed MV2 content scripts incorrectly injecting into guarded hosts because MozDocumentMatcher::MatchesURI was not consulting CheckGuarded when mCheckPermissions was false; Fixed in Firefox 153 – Bug 2041393
• Added support for accessing ObservableArray attributes (such as adoptedStyleSheets) from XrayWrappers and extension content scripts, unblocking extensions that rely on this Web API; Fixed in Firefox 153 – Bug 1751346
• Wired runtime_blocked_hosts and runtime_allowed_hosts enterprise policy settings through ExtensionSettings to allow administrators to restrict extension host permissions on managed devices, starting in Firefox 153 – Bug 1805205
  • Thanks to Mike Kaply for implementing this enterprise policy enhancement.

WebExtension APIs

• Fixed promiseTabWhenReady blocking indefinitely on discarded tabs, preventing cleanup of associated resources and potentially causing memory leaks; Fixed in Firefox 153 – Bug 1653876
• Fixed webNavigation.onCommitted being dispatched twice for cross-origin iframes loaded under Fission, caused by a redundant OnStateChange trigger firing in addition to OnLocationChange; Fixed in Firefox 153 – Bug 1750196

DevTools

• Chris Vander Linden made the Search input component shared as we plan to use it in the Netmonitor as well (#2019260, #2027580, #2027582)
• pullmana8 improved error management in the DevTools protocol (#2031735)
• Chris H-C :chutten removed Legacy Telemetry devtools instrumentation (#2039650)
• :glob ✱ fixed an issue in the Inspector where the swatch color for variable in @starting-style rule could have the wrong color (#2016778)
• Nicolas Chevobbe [:nchevobbe] exposed heading level more clearly in the accessibility tree (#1588784) and in the accessibility highlighter (#2044904)

• Julian Descottes [:jdescottes] migrated the markup view to HTML (from XHTML) to fix an issue when editing the markup (CodeMirror 6 does not support XHTML) (#2028058)
• Nicolas Chevobbe [:nchevobbe] fixed an issue in Netmonitor search where it could appear the the search stalled (#2042405)
• Hubert Boma Manilla (:bomsy) added more connection information (ECH, Delegated Credentials, OCSP, Private DNS, …) in Netmonitor Security tab (#2036404)

WebDriver

• Khalid AlHaddad improved the window manipulation commands in Marionette and WebDriver BiDi to allow individual window geometry properties, such as x, y, width, and height, to be adjusted independently.
• Khalid AlHaddad updated our codebase to use constants instead of hardcoded strings for all our session data types.
• Alexandra Borovova updated the “emulation.setLocaleOverride” command to also apply a locale emulation in dedicated and shared workers.
• Alexandra Borovova fixed a regression when there would be no “script.realmCreated” events after the cross-origin navigation.

Search and Urlbar

• Dharma updated context search actions to trigger search instead of entering search mode @ 1945080
• Daisuke and Drew worked on a lot of Nova updates, including ensuring Nova is tested @ 2041255, 2030183, 2019168, 2044849, 2033583
• Moritz has worked on several refactorings to allow the urlbar to be used in content @ 2039828, 2039298, 2041280
• Middle click paste replaces content was fixed by Moritz @ 2042893
• Michel added feature to show registrable domain on desktop after its implementation on mobile @ 1986161

Highlights

• Maxx Crawford added a pref to hide the New Tab logo so users can opt out of branding without altering page layout or resorting to CSS overrides.
• Harshit enabled video overlay detection in Nightly 153, allowing you to use the context menu to control videos on more pages! We plan on letting this ride out in Firefox 153.
  • You can try it out on this Instagram reel in Nightly

• A note to WebExtension authors – as part of a planned deprecation announced last month, executeScript and insertCSS are now restricted from moz-extension pages starting in Firefox 152 – Bug 2015559
• Nicolas Chevobbe [:nchevobbe] added support and debugging for modern attr()(which is enabled on Nightly) (#2014751)

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

Volunteers that fixed more than one bug

• Sam Johnson
• Sebastian Zartner [:sebo]

New contributors (🌟 = first patch)

• Immaculate Atim: Switch to using an array instead of an object string for browser.backup.enabled_on.profiles
• liz: Screenshots overlay visible on both splitview browsers
• 🌟 Rahman Mahmutović [:r_m]: Can’t change content in box model in inspector for box-sizing:border-box elements
• Takeru Mitsumori: Fix typo in ID name about-translations-swap-langauges-icon in about-translations.html
• 🌟 Freya Arbjerg [:freyacodes]: Blackboxed columns are ignored
•  tom.passarelli: tab-preview-panel emits unpaired popupshown/popuphidden events, breaking sidebar autohide

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• As part of the work for the Project Nova about:addons page restyling, the about:addons sidebar has been migrated to the moz-page-nav and moz-page-nav-button reusable components, improving accessibility and visual consistency with the Firefox Desktop about:settings page – Bug 1881767

WebExtensions Framework

• Implemented WebExtensions negative permissions infrastructure, providing the foundations for enterprise policy “blocked host permissions” features – Bug 1745823
• Restricted host permission changes for MV3 extensions force-installed via enterprise policy (matching similar behaviors provided by Chrome enterprise policy behaviors) – Bug 1904054
  • Thanks to Mike Kaply for the implementation of this enterprise policy enforcement feature.

WebExtension APIs

• Fixed handling of <all_urls> as an API permission in Manifest V3, ensuring the permission is correctly initialized on extension install – Bug 1758306

DevTools

• Rahman Mahmutović [:r_m] made it possible to edit width/height in the box model section of the Layout panel (#1717176)
• Sebastian Zartner [:sebo] improved toggling tools driving in-page highlighters (e.g. the Measuring) (#1262773)
• Sebastian Zartner [:sebo] added a setting to control visibility of HTML comments in the markup view (#1455294)
• Freya Arbjerg [:freyacodes] fixed an issue in script blackboxing (#2036767)
• Alexandre Poirot [:ochameau] replaced custom preference to log RDP messages with MOZ_LOG (#1622857)
• Alexandre Poirot [:ochameau] fixed retrieval of garbage collected script text content (#1758454)

WebDriver

• Sameem updated the “Take Element Screenshot” command from WebDriver Classic to crop screenshots of elements which exceed the viewport. This aligns with the specification and avoids errors when attempting to capture huge elements.
• Alexandra Borovova updated the events for new top-level browsing contexts: we will not send anymore “browsingContext.domContentLoaded” and “browsingContext.load” events for them, instead the “browsingContext.contextCreated” event will be sent when a tab is ready to be used. This is required to align with the expected per-spec behavior.
• Henrik Skupin landed a patch allowing geckodriver to gracefully shut down Firefox when geckodriver itself is terminated.
• Hiroyuki Ikezoe disabled Firefox’s “scroll axis lock” feature so WebDriver actions for wheel input devices can scroll in arbitrary directions when using pan gestures.

Lint, Docs and Workflow

• Added a rule to prevent new uses of Preferences.sys.mjs.
• The browser environment globals within ESLint have now been updated. These include Sanitizer, VideoFrame and a few other new ones.
• Temporal, and some other definitions have been added to TypeScript.

New Tab Page

• Much has happened in the last 2 weeks! Here’s a full bug list, and here are some highlights.
• Dre fixed the List widget that was creating a new list too eagerly on the New Tab Page (2033592) — prevents accidental list creation and improves the Lists UI reliability.
• Maxx Crawford fixed Weather widget small card layout issues with opt-in location options and an error message displayed, resolving card overflow and removing the spurious opt-in error so users see a compact Weather card and correct location prompts on New Tab.
• Reem Hamoui added key dates state to the Sports widget, enabling the Sports card to surface event deadlines/key-date highlights on New Tab so sports users see timely date info.
• Scott Downe added a manage widgets option to the New Tab nova widgets context menu, giving users a direct context-menu entry to open the widget management flow from any widget with Nova enabled.
• Scott Downe added a reusable Newtab widget base component to centralize lifecycle, focus/keyboard handling, DOM templates, and telemetry hooks, reducing duplication and making widget behavior more consistent; see Newtab widget base component.
• Dre converted per-widget expansion handling to a shared widget expansion handler to unify expand/collapse state management and prevent widgets from incorrectly retaining or losing expanded state; see Convert widget expansion handling to shared widget expansion.
• Nina Pypchenko [:nina-py] updated the Sports widget to populate the “follow teams” state from the /teams endpoint, so follow/unfollow toggles now reflect server-side subscriptions and reduce incorrect follow states.
• Scott Downe moved widget menu items within New Tab widgets to standardize menu ordering and action grouping, so users find Add/Remove/Configure entries in expected positions across platforms.
• Dre fixed a World Clock city search bug for the word clocks widget, restoring expected search filtering/matching so city lookups return correct results.
• Scott Downe fixed an issue where the New Tab small weather widget size change didn’t always apply by correcting the widget size update path (JS/CSS layout interactions), improving consistent rendering for small-tile weather across responsive breakpoints and platforms; see Newtab small weather widget size change doesn’t always work.
• Nina Pypchenko [:nina-py] added a group stage section to match highlights in the sports widget on New Tab so users now see stage-aware grouping and stage labels on match highlight cards, making tournament context (group vs knockout) visible while browsing highlights.
• Dre fixed the small world clock widget not expanding to large while editing clocks so users can enter edit mode and expand the widget as expected; the change wires the edit-mode resize handler to update widget size/class during edits.
• Maxx Crawford added WCW OMC message strings so World Cup widget messaging flows on New Tab now display the correct copy (localized where available) instead of falling back to missing-text behavior.
• Reem Hamoui added a “View all” button and a list view for the results tab at medium widget size so Sports widget users on medium New Tab tiles can expand results and scroll full lists without resizing the widget.
• Maxx Crawford added WCW “Watch Live” stream strings to the Sports widget strings bundle so the widget can surface a localized “Watch Live” CTA for applicable events.
• Dre restored VoiceOver reachability for Edit/Remove in World Clock on macOS so macOS VoiceOver users can now focus and activate clock Edit/Remove controls thanks to accessibility role/label and focus-order fixes.
• Maxx Crawford removed the persistent browser logo when all new-tab features (Top Sites, widgets, content feed) are disabled by adding a conditional render guard in the New Tab component, preventing an orphaned logo (2041033).
• Mike Conley added New Tab jest tests to the node tests Tier 1 CI job Run newtab jest tests as part of node tests Tier 1 job to catch regressions earlier in CI
• Irene Ni shipped multiple visual fixes for the Sports widget Sports widget – various visual fixes (spacing, truncation, icon alignment, clipping) to improve readability and layout on constrained viewports.

Picture-in-Picture

• kpatenio adjusted our YouTube site specific wrapper so that the URL bar toggle appears more reliably, especially when selecting videos from the YouTube search page.
• Thanks to Sylvestre for patching some bugs to prevent some spurious console errors!
• Niklas fixed captions on autopip videos failing to sync with the origin videos.

Performance Tools (aka Firefox Profiler)

• Firefox Profiler now has a CLI! We also added a profiler-analysis skill to the Firefox codebase. Once you capture a performance profile, you can ask Claude or an AI to analyze it by providing a link or local path. You can use it to analyze a performance regression or debug an issue if you have a profile at hand.
  • https://www.npmjs.com/package/@firefox-devtools/profiler-cli
  • You can install it with npm install -g @firefox-devtools/profiler-cli@latest

Search and Urlbar

Nova UI refresh

• Drew and Daisuke continued working on reorganizing styles and updating the urlbar for Nova.
• 2019154, 2019152, 2041501, 2040532

Suggest

• Drew landed several Suggest improvements: realtime suggestions colors, sports suggestions received World Cup tweaks, and online Suggest via OHTTP was enabled for eligible users in Firefox 153.
• 2040561, 2039753, 2035614, 2038843

Adaptive autofill

• James fixed soft-block counting to track autofill dismisses, rather than consecutive backspaces on the same autofill, and added telemetry to measure URLs reintegration after blocking.
• 2040819, 2037177

Quick actions

• Dharma created a new Firefox Labs quick action, fixed the Update action button, and re-enabled ScotchBonnet in some tests that were not updated yet.
• Caleb added Calculator support for certain unicode operators.
• 2023169, 1928635, 1923383, 2033861

Multi Context Address Bar

• Moritz continued refactoring the urlbar code: converted some of the js modules to not be system modules, fixed dynamic results templates, incorrect reuse of result rows, and keyboard shortcuts on the unified search button panel.
• 2039297, 2036095, 2039844, 2037933, 2030050

Other

• Marco, Drew and Daisuke fixed several intermittent test failures.
• 2038510, 2023908, 2011584, 1938142, 1971091

Search

• Mark removed old WebExtension-based search engines from the source tree, removed loading of search add-ons from resource://search-extensions/.
• Caleb fixed multiple documentation issues and added a test covering searches from a private window.
• 1904613, 2035878, 2037942, 2033545, 2005724

Places

• Marco removed some unnecessary database transactions, fixed the bookmarks panel folder dropdown on Windows, and resolved several intermittent test failures.
• Thanks to Sam Johnson who fixed the bookmark edit panel showing “mobile” instead of “Mobile Bookmarks”.
• 2039534, 1505800, 2008829, 2029541, 2035084

Highlights

• James enabled adaptive autofill in Nightly for testing, which we believe should provide better results in the URL bar when doing autocomplete!
• Jack updated the illustrations shown on some of our error pages to match the latest approved designs, giving users more polished artwork when the browser encounters connection or security errors!

• Controls for the Memories feature can now be set during Smart Window onboarding

 

• We’ve disabled the CSS filter implicitly applied to WebExtension pageAction SVG icons across all release channels starting in Firefox 152, completing the deprecation
  • NOTE: The blog post published at WebExtensions API changes in Firefox 149-152 provides to extensions developers more details about this deprecation and links to the related MDN docs.

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

Volunteers that fixed more than one bug

• Amin Amir
• Pranjali Srivastava
• Sam Johnson

New contributors (🌟 = first patch)

•  🌟:23rd: Regression: The new swipe-to-navigation indicator stucks for a moment, when deciding not to navigate the other page
• 🌟Akeem Omosanya: Remove commented-out code in SearchService.sys.mjs
• Amin Amir:
  • 🌟Fix browsingContext.sys.mjs to assign to #contextCreatedHandled instead of contextCreatedHandled
  • Fix missing WITHOUT ROWID SQLite performance optimization in SERPCategorization.sys.mjs
• 🌟Sahaj: Suggest the default target language for translation after changing the detected source language
• 🌟JIANG Zhirui: Breakpad build failed on Windows using VS2026 due to removal of stdext
•  John Iweh: Add “Open in New Tab” and “Open in New Container Tab” options to the context menu for Tabs from Other Devices
• Jak: Bookmarks and History – should respect the “When you open a link, image or media in a new tab, switch to it immediately” setting
• 🌟Andy [:rgbcmy]: Autoplayed next video should also be PIP
•  konyhéa: “Escape” key should collapse the expanded on hover sidebar launcher even if hover is still active.
•  Pranjali Srivastava:
  • Remove icon property from sidebar extensions
  • Show language-agnostic SelectTranslations context menu item when the source and target languages are the same

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• Fixed long-standing regression on the autocomplete and datalist popups for extension inline options pages on about:addons (introduced in Firefox 68 by Bug 1532724, fix shipping in Firefox 152) – Bug 1595158

WebExtensions Framework

• Fixed access to web-accessible resources declared with <all_urls> from sandboxed documents (null-principal URLs), restoring extension redirects from the context-menu search flow, starting in Firefox 152 – Bug 2033905

WebExtension APIs

• Added exhaustive test coverage for tabs.move() against additional edge cases related to split-view tabs – Bug 2029092

DevTools

• Andreas Farre improved the Session History tab in the Application panel (still behind devtools.application.sessionHistory.enabled)
  • added support for remote debugging (#2014064, #2016121)
  • made sure that calls to History.replaceState are reflected in the UI (#2037359)
• Julian Descottes [:jdescottes] fixed the most frequent DevTools crash we were observing in Telemetry, adding a guard against IDBTransaction errors when retrieving breakpoints in the Debugger (#2030260)
• Nicolas Chevobbe [:nchevobbe] fixed the image preview tooltip for relative URLs images in constructed stylesheet (#2035503)
• Julian Descottes [:jdescottes] reduced the overhead we had because of network requests monitoring by only decoding response content when the user actually want to see the response (#2026228)

WebDriver

• Amin Amir cleaned up an incorrect variable assignment in our browsingContext module.
• Logan Rosen updated stale references and broken links in our documentation about Marionette.
• Sameem improved the Marionette and WebDriver BiDi screenshot commands to enforce maximum allowed dimensions.
• Leo McArdle fixed the regression in the “log.entryAdded” event, which lacked an error message in the “text” field for the messages of type “error”.
• Henrik Skupin fixed an issue in Marionette where WebDriver:Navigate and WebDriver:Refresh did not handle errors when the underlying navigation failed.
• Henrik Skupin improved geckodriver to detect an early Firefox exit during startup on Android, avoiding up to 60 seconds of unnecessary connection attempts.
• Henrik Skupin updated the geckodriver CI build job to produce a universal macOS binary supporting both x64 and aarch64.

Lint, Docs and Workflow

• Sylvestre ported some linters (e.g. file-whitespace, test-manifest-toml, license, file-perm, rejected-words & more) to Rust to help improve the runtime of the code review bot.
• Dale has been working on migration to moz-src for customkeys, dom/quota and odom/geolocation
  • https://arewemozsrcyet.com/

New Tab Page

• We did our first region-specific trainhop on May 11th (just 15% of the US), and turned on HNT Nova (and sometimes Widgets) for those clients to get some advance-data of its behaviour in the wild! A note that HNT Nova gets turned on for everybody when Firefox 151 ships on May 19th.
  • We’ll be launching a similar experiment in the DE, probably on May 12th, also at 15% population.
• Most of the team is heads down building out a sports-tracking widget, attempting to get that ready in time to be generally available for the upcoming World Cup event.
• Dre landed a new world clock widget, which is currently off by default, but pretty snazzy!

Search and Urlbar

• Nova (URL Bar Design Refresh)
  • Drew and Daisuke continued their work on Nova styling for the Address bar (input and view).
• Search and Suggest
  • Drew finalized two bugs for World Cup and sports suggestions, which were landed and uplifted: one to update the localization string for scheduled games and another to show both teams’ icons in suggestions. Drew also landed and uplifted a fix for rich search suggestion icons being forced into a square aspect ratio.
  • Standard8 updated Ecosia favicons to the latest branding, including QA testing and publishing.
• Settings Redesign (SRD)
  • Stephanie landed a test to ensure search suggestion settings are hidden when quicksuggest is disabled, as well as a patch to resolve TypeScript issues in search.mjs, and is adding test coverage to confirm removed search engines are not displayed in the default engines dropdown.
• General URL Bar and Component Updates
  • Daisuke landed implementation of the context menu on URL bar results, and a fix to show the loading URL in the URL bar when starting up with a homepage.
    • Marco is working on several tasks, including a PDF download / focus stealing issue and allowing arrays to be bound in Sqlite.sys.mjs. Marco also worked on fixes related to Places, such as avoiding replacing the favicons database if it is not corrupt.
  • Standard8 finalized the URL bar test manifest split. Standard8 also upgraded us to TypeScript 6.
  • Moritz landed a fix for URL bar abandonment telemetry being recorded when clicking an engine in the unified search button popup (Bug 2032973), which was also uplifted. Moritz also simplified search mode switcher item activation in tests, and made it so that the unified search button popup closes when installing an open search engine.

Smart Window

• natural language starting with tab close/undo 2035343 with expandable action log 2031508

• assistant rendering feedback up/down 2032994 and markdown table 2027029
• nova styling blur 2027877 and suggestions 2026823
• accessibility screen reader 2028676 and keyboard focus 2037565
• optimize conversation starters extra requests 2030005 and caching 2033430

Storybook/Reusable Components/Acorn Design System

• Nova token updates occasionally, focused on SRD

UX Fundamentals

• Added support for the “SEC_ERROR_CA_CERT_INVALID” certificate error to the Felt Privacy error pages. – 2035942

Settings Redesign

• Settings redesign is being tested and will hopefully go out in Firefox 152!

Highlights

• The profile backup mechanism has been enabled by default for all desktop platforms in Nightly, as well as Beta! The current plan is to have this ride out to Firefox 151 for Windows, macOS and Linux on May 18th!
  • This feature, when enabled, will create a copy of your profile data in the background and store it in a single file on your file system that you can restore from.
  • You will be able to manage this feature in Settings under Sync (for now)
    • 
  • You can read more about the feature here
• As followups to the recent addition to the WebExtension tabs API to support the new SplitView tabs feature, tabs.group() and tabs.ungroup() have been fixed to work correctly with split view tabs, and fixed split views being prepended instead of appended to tab groups when adopted into a new window – Bug 2029099 / Bug 2029534
• Adaptive autofill has been enabled on Nightly.
  • Previously, autofill only completed domains (e.g. typing red autofilled reddit.com). Now it can also complete full URLs for pages you visit often (e.g. red → reddit.com/r/firefox), learning from what you actually click in the address bar. If a suggestion isn’t helpful, you can now dismiss it so autofill learns what not to show you too.
    • If you run into issues or have feedback, you can file a bug here!
• Markus Stange [:mstange] implemented dynamic toolbar on top in RDM (#1978145), but also implemented some static skeleton UI so it’s closer to what we actually have in Firefox for Android
  • dynamic toolbar is behind a pref: devtools.responsive.dynamicToolbar.enabled
  • it can be put on top by setting devtools.responsive.dynamicToolbar.onTop, otherwise it’s at the bottom
  • 

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

Volunteers that fixed more than one bug

• Amin Amir
• aoia7rz7l
• Chukwuka Rosemary
• DrSeed
• Frédéric Wang Nélar
• japandi
• John Iweh
• jonathancabera
• Josh Aas
• Keji Bakare
• kofoworola shonuyi
• konyhéa
• liz
• Mathew Hodson
• Okhuomon Ajayi
• Oluwatobi
• ROSHAAN
• Sam Johnson

New contributors (🌟 = first patch)

•  Anthony Mclamb: Disable the legacy Edge migrator
•  Amin Amir
  • 🌟Fix browsingContext.sys.mjs to assign to #contextCreatedHandled instead of contextCreatedHandled
  • Fix missing WITHOUT ROWID SQLite performance optimization in SERPCategorization.sys.mjs
  • 🌟 Amine Zroual: Omitted maxResults property not handled correctly in getRecentlyClosed
• any1here: install_sig_alt_stack incorrectly checks mmap’s return value
• 🌟 Armin Ulrich: Fix MessageHandlerRegistry.sys.mjs calling getExistingMessageHandler with an unused second argument
• japandi
  • Cannot remove amazon.com from top sites list
  • The height of the pinned tabs area should be responsive to the number of pins
  • Use cenum for nsIHelperAppLauncherDialog reason constants to enable better typescript annotations
• Nathan Johnson [:narjoDev]: Remove browser.display.use_system_colors pref
• DrSeed
  • Firefox shows vertical tabs in new windows despite “Hide tabs and sidebar” setting
  • The “Expand sidebar on hover” option is not kept after the vertical tabs are disabled and enabled again
• Keji Bakare:
  • Split view’s focus-outline is clipped on the right side of left tab
  • White space on the right side of left panel in split view
• 🌟 gotyaoi: Reload toolbar button is active on about:newtab
• Itoro James: [A11y][Keyboard Navigation]Cancelling a note via Keyboard Navigation still saves it
• John Iweh: The notification dot is not displayed if the tab is in a Split View
• 🌟 John Iweh: sidebar-shown attribute remains when sidebar.revamp is false
• 🌟 jonathancabera:
  • The Move tab to Split View option is also displayed for the tabs that are within the Split View
  • A Note with long text (1003 characters) is saved by pressing ENTER even if the “Save” button is disabled
  • Tab group guide line becomes disconnected under certain conditions related to split views in vertical tab mode
• Aloys: Remove logic that forces distribution language packs to be reinstalled when upgrading from Firefoxes older than 67
• liz:
  • Create test to ensure maxRenderCountEstimate is never being set to Infinity in virtual-list component in Fx View
  • Button accessible name does not convey its function: missing topic context (Settings dialog > Topics dialog > buttons Following/Unfollow/Blocked/Unblock)
• Mary cathline: Tab Group Label does not respect touch density in vertical tab bar
• 🌟 Brandon Lucier: Popups opened with window.open give window type normal instead of popup
• karan68: [dialog] New Shortcut dialog needs a label/accessible name
• 🌟 Vector: Button does not programmatically indicate that it opens a dialog (Recent activity section > story card > ••• disclosure > Delete from History button)
• 🌟 Osoble: Update font size and weight for synced tabs device name headers in Firefox View
• konyhéa:
  • Add test for sync admin disabled to browser_syncedtabs_errors_firefoxview.js
  • Check all second paramaters for TestUtils.waitForCondition in Fx View test files
  • Recently Closed Tabs, Tabs from Other Devices, and History pages should have Cmd / Ctrl + Click on a link open the link in the new background tab.
• Noble Chinonso: #shouldHandleEvent in SidebarTreeView.js compares event.keyCode to string values, causing Home/End keys to never be handled
• Pranjali Srivastava: Add a test to verify that the space above tabs is consistent across PB, LWT and sizemode (where appropriate)
• Okhuomon Ajayi:
  • More spacing is needed between the tab note icon and the close icon on the tab
  • The tabs in vertical mode collapsed state are positioned differently in Split View
  • Keep vertical split view tabs stacked vertically even when the sidebar is expanded when expand on hover is enabled
  • Vertical split view tabs can be too big or small when tabs are overflowing
• 🌟 Rishan: Fix duplicated arrow function in browser_history_sidebar.js
• Chukwuka Rosemary:
  • “Forget About This Site” context menu option missing from Firefox View history
  • Long strings are not displayed properly on the about:opentabs page search filed
  • Add test for Forget This Site option in Fxview history context menu.
• ROSHAAN:
  • 🌟Tab note background colour is incorrect for default light theme
  •  [win/linux] The splitter between content areas does not match Figma spec
  • Fix typo in OpenInTabsUtils.confirmOpenInTabs()
• Sameeksha: Disclosure button expanded/collapsed state not programmatically defined (Customize button)
• kofoworola shonuyi:
  • 🌟Actually hide or remove sidebar-shown attribute when in fullscreen.
  • Add a test for checking sidebar-shown attribute in fullscreen mode
• 🌟 Sayd Mateen: Page URL is displayed as tab name when page’s contains about:reader?</a></p> <p>

• Oluwatobi:
  • Unable to delete selected history entries from sidebar
  • Incorrect Sidebar button state/tooltip hover text
  • The city name heading level doesn’t follow the correct heading level order
• Nishchay [:nish]: Unable to add tabs to old closed tab groups (tabGroupState.splitViews is undefined)

 

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• In preparation for the Project Nova restyling of the about:addons page, we have refactored about:addons into separate per-component ES modules, splitting the monolithic aboutaddons.js and aboutaddons.html into 16 dedicated component files under components/ (with no behavior or UI changes) – Bug 2032014
  • NOTE: if you have working on patches with changes to about:addons internals it is very likely you’ll need to rebase and solve merge conflicts hit on top of this refactoring, the internals are still largely the same as before but don’t hesitate to reach out to the Addons team if you have doubts / questions or need help to figure out how to adapt your patch of top of these changes

WebExtensions Framework

• Fixed exportFunction to preserve the constructibility of the wrapped function instead of unconditionally making all exported functions implicitly as constructors – Bug 2033173
  • Thanks to Gregory Pappas for contributing this improvement to the Content Scripts’ Xray Wrappers helpers!
• Fixed a Firefox 151 regression where extension content scripts accessing location.ancestorOrigins caused subsequent page script reads of the same property to fail with “Permission denied”, breaking sites like Gmail – Bug 2034329
  • Thanks to Simon Farre for promptly investigating and fixing this recent regression!

WebExtension APIs

• Updated sessions.getRecentlyClosed() to remove the hardcoded cap when maxResults is omitted – Bug 1392125
  • Shoutout to Amine Zroual for contributing this enhancement to the sessions WebExtensions API!

DevTools

• Artem Manushenkov fixed an issue where autosuggestion popup was removing overridden indicators from properties in the Inspector (#1983408)
• Andrea Marchesini [:baku] fix DevTools cookie header serialization for long cookies, which could lead to cookies not being visible in Netmonitor (#2031299)
• Julian Descottes [:jdescottes] fixed a toolbox crash that was happening we couldn’t find a localization file (e.g. when using a language pack on Nightly) (#2028930)
• Nicolas Chevobbe [:nchevobbe] improved @container tooltip so it show the value of variables used in style()(#2030239), has enough contrast in dark mode (#2033782) and contains a link to select the container (#2031688)
  • 
• Hubert Boma Manilla (:bomsy) is making good progress on migrating the Console to CodeMirror 6 (#2032758, #2026569)

Fluent

• We’re now at over 72% of our strings being Fluent! Got a component still using .properties? Convert when you can!
• 

Migration Improvements

• Thanks to dao for fixing a recent alignment issue in the migration wizard dropdown
• Thanks to volunteer contributor Anthony Mclamb for his patch that disables the legacy EdgeHTML Edge migrator! Once that finishes rolling out, presuming no surprises, we’ll go ahead and remove the migrator entirely.

New Tab Page

• Nova for New Tab has ridden the trains to Beta! It will be enabled by default, globally, when Firefox 151 goes out to release on May 19th
  • It’s possible that we’ll do a train-hop coupled with an experiment to enable HNT Nova for a few clients a bit earlier.
• Maxx Crawford enabled Nova designs for New Tab, rolling out the updated layout, widgets, and customization panel behind HNT Nova flags.
• Maxx Crawford fixed the Nova content feed to render the intended four‑column layout by correcting CSS grid breakpoints.
• Maxx Crawford resolved a first‑load failure in the Weather widget by fixing init order and fetch timing, eliminating the “Oops” error.
• Maxx Crawford synchronized the Weather toggle between about:preferences#home and the panel via the shared showWeather pref to prevent desync.
• Maxx Crawford updated Nova grid focus order to align tab flow with visual order for keyboard users.
• Maxx Crawford fixed critical UI issues in Lists and Timer widgets covering overflow, controls, and layout stability.
• Maxx Crawford guarded document.dir access in Nova render paths to avoid startup cache worker errors and improve startup stability.
• Rolf added a new normalization method for the inferred interest vector to stabilize topic relevance across sessions.
• Rolf prevented unnecessary content refreshes during Pocket New Tab experiments, reducing jank and bandwidth.
• Sameeksha defined the Customize button’s expanded/collapsed state programmatically using aria-expanded for better a11y.
• liz clarified follow/unfollow/blocked button names with topic context so screen readers announce clear actions.
• Vector marked the Delete from History control as opening a dialog via aria-haspopup=dialog for assistive tech.
• Scott Downe fixed a regression that flipped the Wallpapers pref off, restoring user selections.
• Irene Ni corrected privacy link color and focus styles for contrast and keyboard visibility.
• Reem Hamoui added a wallpaper toggle reset in the Nova customization panel so users can quickly restore default wallpapers without extra steps.
• Reem Hamoui fixed the Customize pencil button to match the Nova spec, aligning placement and iconography for visual consistency.
• Dre updated the ‘Fresh new’ wallpapers copy to a clearer, localized message for better comprehension.
• Irene Ni fixed Nova privacy link color and focus styles to meet contrast and focus ring guidelines, improving accessibility on New Tab.
• Irene Ni adjusted Sponsored tile character limits to prevent truncation/overflow, yielding cleaner titles across grid and wide tiles.
• Scott Downe fixed a regression that flipped the Wallpapers user pref to false, restoring wallpapers for affected users and preventing unintended disablement.
• Reem Hamoui hooked the wallpaper check into the new toggle logic so the Customization Panel accurately reflects wallpaper availability and state.
• Irene Ni landed Nova UI updates for the Daily Briefing 3-pack card, improving spacing, type scale, and tap targets.
• Reem Hamoui added a wallpaper toggle reset in the Nova customization panel so users can quickly restore default wallpapers without extra steps.
• Reem Hamoui fixed the Customize pencil button to match the Nova spec, aligning placement and iconography for visual consistency.
• Dre updated the ‘Fresh new’ wallpapers copy to a clearer, localized message for better comprehension.
• Irene Ni fixed Nova privacy link color and focus styles to meet contrast and focus ring guidelines, improving accessibility on New Tab.
• Irene Ni adjusted Sponsored tile character limits to prevent truncation/overflow, yielding cleaner titles across grid and wide tiles.
• Scott Downe fixed a regression that flipped the Wallpapers user pref to false, restoring wallpapers for affected users and preventing unintended disablement.
• Reem Hamoui hooked the wallpaper check into the new toggle logic so the Customization Panel accurately reflects wallpaper availability and state.
• Irene Ni landed Nova UI updates for the Daily Briefing 3-pack card, improving spacing, type scale, and tap targets.

Search and Urlbar

• Marco has fixed a couple of issues with the places databases to try and improve stability. This should help with avoiding users losing bookmarks or favicons.
• Work continues on the new separate search bar to improve the functionality, e.g. allowing middle click to perform a search in a new tab, avoiding performing a search when adding a search engine.
• Work also continues on the new Nova layouts.

Smart Window

• uplifted 10 bugs to 150.0.1 dot release addressing initial user feedback from diary study and Connect
  • jump to bottom of conversation 2028692
  • stop streaming button 2029204
  • back/forward navigation from assistant 2029229
  • dark mode for various chips 2024499
• search engine switching from smart bar 2021973
• Nova styling within smart window 2026794

Storybook/Reusable Components/Acorn Design System

• Dustin converted moz-breadcrumb-group variables into JSON design tokens Bug 2029181 – Convert moz-breadcrumb-group variables into JSON design tokens
• Dustin converted moz-box-* variables into JSON design tokens Bug 2029180 – Convert moz-box-* variables into JSON design tokens
• Dustin converted moz-promo variables to JSON design tokens Bug 2029190 – Convert moz-promo variables into JSON design tokens
• Dustin converted moz-reorderable-list variables to JSON design tokens Bug 2029191 – Convert moz-reorderable-list variables into JSON design tokens
• Dustin converted moz-visual-picker variables to JSON design tokens Bug 2029193 – Convert moz-visual-picker-item variables into JSON design tokens
• Dustin updated browser-shared.css so it passes use-design-tokens Bug 2022985 – Update browser-shared.css so it passes use-design-tokens
• Dustin updated popup.css so it passes use-design-tokens Bug 2022979 – Update popup.css so it passes use-design-tokens
• Jon added opacity tokens and added opacity to use-design-tokens stylelint rule  Bug 1955325 – Create opacity tokens
• Jon converted toolbar design tokens to JSON Bug 2017970 – Convert toolbar design tokens to json
• Anna fixed moz-select with panel-list drop-down size inconsistency Bug 2032365 – Applications Action drop-down menus sometimes have a different size when opened
• Anna fixed issue with the disabled state of moz-radio component Bug 2027123 – moz-radio disabled state cannot be changed while the moz-radio-group is disabled
• Anna updated moz-button and moz-box-button components to prevent label corruption when accesskeys are present and the label changes.   Bug 2022326 – moz-button with accesskey label becomes corrupted when l10nId updates dynamically

UX Fundamentals

• The error pages shown when a server sends back an invalid response header or an unsupported content encoding now display accurate, context-specific messages. The invalid response header page also gained a helpful list of next steps. – 2027209
• In progress: The error page illustrations are being replaced with new artwork, and the system now supports per-illustration size configuration, giving each image the ability to define its own appropriate dimensions. – 2031837

Settings Redesign

• Tim converted settings related to Accessibility page to config-based pane Bug 1968116 – Convert settings related to Accessibility page to config-based settings
• Benjamin converted Privacy & Security page to the config-based pane Bug 1968112 – Convert settings related to Privacy & Security page to config-based settings
• Finn integrated Firefox Labs page into setting-pane config Bug 2021047 – Integrate Firefox Labs page into setting-pane config
• Anna converted Firefox Updates section to config-based prefs Bug 1990961 – Convert Firefox Updates section to config-based prefs
• Mark Kennedy added moz-promo, that is welcoming users to the redesigned settings Bug 2015093 – Add a moz-promo to welcome users to the redesign
  • 
• Anna added possibility to search for actions in the redesigned “Applications” section Bug 2020370 – It’s no longer possible to search for actions in the new “Applications” section
• Anna fixed the Settings navbar layout breakage

The redesign of Firefox Settings is now enabled by default in Nightly! With this change, we are making it easier for people to customize Firefox and discover the controls that matter most to them. The redesign improves navigation and organization, updates labels and descriptions, and uses a new underlying architecture that will make Settings easier to update over time.

Firefox Settings have grown a lot over the years. Our research showed that some areas had become crowded and more difficult to navigate, and that important controls could be hard to discover. Some terminology and layouts had also become inconsistent over time. Internally, the existing structure also made Settings harder to maintain and evolve over time.

Here are some of the changes you’ll notice:

• More pages within Settings, with less content per page
• Clearer grouping and better flow between related controls
• Improved labels and helper text
• Consistent use of our design system throughout

While the organization of Settings has changed, all your existing choices and preferences remain in place. You can always use the search bar to jump straight to what you’re looking for.

We plan to ship the redesign to the Release channel in Firefox 152. You will continue to see changes in Nightly, and we welcome feedback, especially in Mozilla Connect.

Customization has long been a core part of Firefox, and this redesign is intended to continue improving how people discover and manage their browser settings. We appreciate all of the feedback from the community so far on this project and look forward to refining the experience with your input!

Highlights

• Import attributes will be supported for WebExtensions, starting in Firefox 150!
  • This allows WebExtension authors to import CSS module scripts and JSON into their JavaScript modules.
  • Examples:
    • import sheet from ‘./styles.css’ assert { type: ‘css’ };
    • import schema from “./policies-schema.json” with { type: “json” };
• The Web Serial API is now available for testing in Firefox Nightly!
  • See https://fosstodon.org/@balloob/116398481380578311 for more details on how to test this our yourself.
• Dharma created a new quick action for Firefox Library
  • You can test this out in Firefox Nightly 151 by typing “library” in the URL bar

• Alexandre Poirot [:ochameau] Enabled the JS Tracer DevTool by default on Nightly
  • Read up on how to use the JS Tracer to analyze JavaScript usage on the web here

Friends of the Firefox team

Resolved bugs (excluding employees)

Volunteers that fixed more than one bug

• Chris Vander Linden
• Chukwuka Rosemary
• DrSeed
• EJiro Oghenekome
• Frédéric Wang Nélar
• Itoro James
• japandi
• John Iweh
• jonathancabera
• Josh Aas
• Justin Peter
• Keji Bakare
• kofoworola shonuyi
• konyhéa
• Noble Chinonso
• Okhuomon Ajayi
• Oluwatobi
• Pranjali Srivastava
• ROSHAAN
• Sameeksha

New contributors (🌟 = first patch)

• 🌟 Ben: UI issue in AST locale in Responsive design mode > (open Device picker) > Edit List… > Add Custom Device
• Brian Tsoi [:btsoi]: Create a badram checking library
• 🌟 Chidimma Okoloigwe: Port over tests in browser/base/content/test/sidebar
• japandi:
  • 🌟Use cenum for nsIHelperAppLauncherDialog reason constants to enable better typescript annotations
  • The height of the pinned tabs area should be responsive to the number of pins
  • Tab notes should not be saved when input contains only spaces
• Nathan Johnson [:narjoDev]: Remove browser.display.use_system_colors pref
• DrSeed:
  • 🌟Remove the defaultLauncherVisible Nimbus variable
  • Firefox shows vertical tabs in new windows despite “Hide tabs and sidebar” setting
  • The “Expand sidebar on hover” option is not kept after the vertical tabs are disabled and enabled again
• EJiro Oghenekome:
  • 🌟Tests required for view>sidebar menu items
  • Remove old sidebar icons no longer and replace with new.
  • Rename SidebarController.initializeUIState() and SidebarState.loadInitialState()
• Keji Bakare:
  • 🌟 Hide “Open Link in Split View” menu option for pinned tabs
  • The right tab name and icon slightly move when the Split View is selected
  • Split view’s focus-outline is clipped on the right side of left tab
• 🌟 gotyaoi: Reload toolbar button is active on about:newtab
• 🌟 Hailia: Copied profile edit page heading should enclose profile name in quotes
• geppy: Rename –theme-graphs-* CSS variables
• Itoro James:
  • 🌟 [FxMS Docs] Document the feature callout anchor selector’s ::%shadow% token
  • [A11y][Keyboard Navigation]Cancelling a note via Keyboard Navigation still saves it
• John Iweh:
  • 🌟 The notification dot is not displayed if the tab is in a Split View
  • sidebar-shown attribute remains when sidebar.revamp is false
• jonathancabera:
  • 🌟 A Note with long text (1003 characters) is saved by pressing ENTER even if the “Save” button is disabled
  • Tab group guide line becomes disconnected under certain conditions related to split views in vertical tab mode
• Aloys: Remove logic that forces distribution language packs to be reinstalled when upgrading from Firefoxes older than 67
• Mary cathline: Tab Group Label does not respect touch density in vertical tab bar
• 🌟 Brandon Lucier: Popups opened with window.open give window type normal instead of popup
• karan68: [dialog] New Shortcut dialog needs a label/accessible name
• 🌟 Osoble: Update font size and weight for synced tabs device name headers in Firefox View
• konyhéa:
  • 🌟 don’t restrict the sidebar width so much (to better support non-English locales)
  • Add hairline separators between synced tabs device lists on the Recent Browsing page in Fx View
  • Firefox View breakpoint for collapsing the sidebar triggers too late
  • Split view does not show colored outline when used as a group target during dragging
• Noble Chinonso:
  • 🌟 Add the ‘command’ property to the SidebarStateProps definition
  • Timestamp not displayed for items under “Tabs from other devices” in Firefox View Next tab
  • Move tab to Start/ End options are enabled and not working, even if the Split View tab is already at start/en,d and the other view is focused
  • Mismatched closing tag in syncedtabs-tab-list.mjs itemTemplate
  • Do not capitilize “tagName” returned from “WebDriver:GetElementTagName” command
  • #shouldHandleEvent in SidebarTreeView.js compares event.keyCode to string values, causing Home/End keys to never be handled
• Knot False: Remove nsIScriptableUnicodeConverter from services/common/utils.js
• Pranjali Srivastava:
  • 🌟Remove virtualizer pref
  • Add a test to verify that the space above tabs is consistent across PB, LWT and sizemode (where appropriate)
  • In the about:opentabs page the containers icons have no padding on the right side while hovered
• Okhuomon Ajayi:
  • More spacing is needed between the tab note icon and the close icon on the tab
  • Split view container and vertical tabs are misaligned when resizing the sidebar down
  • Vertical split view tabs can be too big or small when tabs are overflowing
• 🌟 Rishan: Fix duplicated arrow function in browser_history_sidebar.js
• Chukwuka Rosemary:
  • 🌟 Remove the max-history-rows pref used in Fx View
  • “Forget About This Site” context menu option missing from Firefox View history
  • Long strings are not displayed properly on the about:opentabs page search filed
  • Add test for Forget This Site option in Fxview history context menu.
• ROSHAAN:
  • 🌟 Tab note background colour is incorrect for default light theme
  • [win/linux] The splitter between content areas does not match Figma spec
  • Fix typo in OpenInTabsUtils.confirmOpenInTabs()
• Sameeksha:
  • 🌟 Remove redundant lazy pref getters in SidebarPinsPromo
  • Dialog lacks accessible name (Recent activity section > ••• disclosure > Delete from History dialog)
• kofoworola shonuyi:
  • Actually hide or remove sidebar-shown attribute when in fullscreen.
  • <sidebar-main> has “sidebar-ongoing-animations” set but never removed
  • Add a test for checking sidebar-shown attribute in fullscreen mode
• 🌟 Sayd Mateen: Page URL is displayed as tab name when page’s <title> contains about:reader?
• Oluwatobi:
  • 🌟 Remove the IE importer and tests
  • Unable to delete selected history entries from sidebar
  • The city name heading level doesn’t follow the correct heading level order

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• Removed obsolete migration logic that forced distribution language packs to be reinstalled when upgrading from Firefox versions older than 67 – Bug 2000797
  • Thanks to Aloys for contributing the changes needed to cleanup this old XPIProvider migration logic

WebExtensions Framework

• Fixed a regression where WebRTC permission popups were queued and suppressed while an extension popup was open – Bug 1982832

WebExtension APIs

• Fixed an edge case where tabs.move would revert splitview tabs order while moving splitview tab to a new window  – Bug 2028832
• Fixed windows API reporting window type normal instead of popup for windows opened via window.open() – Bug 2030631
  • Thanks to Brandon Lucier for contributing this small but very much appreciated fix to the windows WebExtensions API!

DevTools

• Nicolas Chevobbe [:nchevobbe] added support for multi-conditions @container rules in the Inspector (#2023125), add specific style for unmatched conditions (#2030236)

• Nicolas Chevobbe [:nchevobbe] added container-name in the @container tooltip (#2030731)

WebDriver

• Henrik Skupin fixed a bug in the WebDriver BiDi session.new command where an empty proxy object was returned in the capabilities when no proxy was requested, even though that is not valid according to the CDDL.
• Henrik Skupin landed support for browser.setClientWindowState, originally started by Dan and continued by Liam DeBeasi, with final fixes and improvements completed after earlier contributors were unable to continue.
• Alexandra Borovova improved the “text” field of the “log.entryAdded” event to better align with Firefox DevTools behavior and Google Chrome WebDriver BiDi implementation.

Lint, Docs and Workflow

• A problem with the ESLint-build builder has been resolved. This had meant that the valid-ci-uses and valid-services-property rules were not being run.
• Work is ongoing to get various css files passing the use-design-tokens rules.

New Tab Page

• You can preview Nova on the New Tab browser.newtabpage.activity-stream.nova.enabled to true, and then opening a few tabs.
  • The browser.nova.enabled pref was just introduced to turn on the Nova design tokens. That’s still very much a work in progress.

Picture-in-Picture

• aoia7rz7l for added PiP wrapper captions support to various public Invidious instances
• chutten removed all legacy PiP telemetry
• sfarre is working on PiP API support and has a patch up integrating it nicely with our native implementation

Search and Urlbar

Search

• Mandy updated the search-config-v2 schema for partnerCodes (2027191)
• Florian fixed a high frequency intermittent test failure in the search code (2009494)
• Standard8 fixed a bug with duplicate keywords for search engines, so that we now prefer the default search engine (2024714)

Nova

• mconley made a rounder search input for about:newtab and about:privatebrowsing (2027144)
• Drew is continuing his work on making Nova updates to the urlbar  (2026859)

New searchbar

• Moritz and Dao continue re-implementing the search bar using urlbar modules  (2027749, 2027578, 2002834, 2025904, 2027565)

Urlbar

• Dharma also fixed a quick action telemetry error (1955058)
• James has been working on Adaptive History for Autofill Improvements (2019695, 2019695, 2021079, 2019719, 2021036, 2028730, 2021039, 2019626)
• Gijs landed a patch so that we use aria-notify instead of A11yUtils.announce for UrlbarView’s “special” announcements (2026753)
• Dale added a tooltip to engines in the unified search panel (2028668)
• Drew has been working on sports suggestions (2025052)
• James fixed a bug where persisted search was not working for Fx versions prior to 148 (2025933)

Smart Window

• preparing for 150 mvp with various uplifts from 151
• telemetry: assistant 2024869, input/suggestions 2009615, MLtelemetry 2019772, settings 2009612
• security: spotlighting 2020807, url ledger 2023001
• polish: autoopen sidebar pref 2029686, memories strings 2029262, report issues link 2029257
• bugs: keeping conversations when switching windows 2026239, switching tabs 2023284, transition fullpage to sidebar 2024781
• a11y: ask button state 2015485, smartbar announce 2016758

Storybook/Reusable Components/Acorn Design System

• From more than two weeks ago (sorry I wasn’t here and forget if they were shared):
  • Finn converted the Settings page nav to match Firefox View/new design Bug 1867385
  • Mark S imported the initial Nova design from Figma Bug 2021477
    • Currently behind browser.design-tokens.nova but moving to browser.nova.enabled today most likely
  • Mark S created an Icon Directory in Storybook – Bug 1990228
• Mark Striemer added breadcrumbs to sub-panes in Settings
• Anna Kulyk fixed arrow keys not working with panel-list variant of moz-select with separators
• Mark Kennedy fixed an display issue with the Applications view not updating when cancelling the Use other option
• Finn Terdal fixed some page navigation issues:page nav leaves a large gap when it first collapses to icon-only, sub-pane content being clipped by sticky search bar, reintroduced the vertical border next to static sidebar in prefers-reduced-motion
• Jules Simplicio landed a UI polish pass for the Settings Redesign with spacing, focus-ring, and contrast tweaks across subpanes, improving readability and target sizes.
  • This also updated some global styling for card, message bar, text input border radiuses/colors and the moz-promo component got a refactor with better support for image styling by default
• Hanna Jones updated copy and illustrations for the Account and sync page, so it’s ready for SRD release
• Osmond Arnesto converted urlbar variables to design tokens, preparing for JSON conversion and Nova import from Figma
• Jon Oliver converted tab variables into design tokens, and set them up in JSON for Nova import from Figma
• Jules Simplicio has been updating variable names in the Figma Nova Components/Styles files so our design token naming is consistent between Figma and central (so we can run our import script for more Nova automation)

UX Fundamentals

• Felt Privacy error pages now support more NSS errors instead of falling through to the legacy page. Updated introductory text for the denied-port-access error. – 2024150
• Fixed a test in browser_aboutCertError.js that was failing on Linux opt standalone and removed the platform skip. – 2028651
• Added clock skew detection to the Felt Privacy error pages. When a certificate error is caused by a wrong system clock, the Felt Privacy error pages now show the same dedicated clock-skew message that the legacy error pages had, and helps guide users to correct their system time. – 2025049
• ​​Fixed misaligned bullet points in the “What can you do?” section of Felt Privacy network error pages, restoring correct visual indentation for that list. – 2028632

Highlights

• The VPN feature is rolling out to users in the United States, the United Kingdom, Germany and France! Read more about it here.
  • And here’s more information about it on SUMO 
    • 
• Split View is now available for users on Firefox 149! Read more about it here.
  • 
• Improvements to tabs.move() split views support: extensions can now swap tabs within a split view, and passing a list of tabs that explicitly separates split-view members will properly unsplit the view to honor the requested ordering – Bug 2016762 / Bug 2022549
• Jeremy added the ability to copy all URLs from multi-selected tabs 1984362 – Share -> “Copy link” for multiselected tabs should copy all the tabs’ information
• Alexandre Poirot [:ochameau] improved performance of the Inspector Rules view by supporting incremental updates, making some perf test 2 times faster (#2018538)
  • perf compare results
• The Tab Notes feature is now live in Firefox 149 in Firefox Labs! We have a few tweaks and fixes coming in Firefox 150 and 151, but we’re mostly collecting feedback from users.
  • 

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

Volunteers that fixed more than one bug

• Chris Vander Linden
• EJiro Oghenekome
• Keji Bakare
• konyhéa
• Noble Chinonso
• Pranjali Srivastava
• Sameeksha

New contributors (🌟 = first patch)

• 🌟Ben
  • Bug 1705177 – Don’t use fixed width for Add Device Save/Cancel buttons. R?nchevobbe!
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1705177
• 🌟Chidimma Okoloigwe
  • Bug 1901274 – Port over tests from browser/base/content/test/sidebar to browser/components/sidebar
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1901274
• Japandi
  • Bug 2015071 – Do not save tab note when input contains only whitespace. R?sthompson
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2015071
• 🌟DrSeed
  • Bug 1982888 – Remove obsolete sidebar Nimbus var r=nsharpley,sfoster
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1982888
• 🌟EJiro Oghenekome
  • Bug 1910902 – Update sidebar icons and references to use collapsed versions. r=nsharpley
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1910902
  • Bug 1938466 – Add tests for View &gt; Sidebar menu items and checked state. r=jsudiaman
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1938466
  • Bug 1952061 – Refactor sidebar state management: rename loadInitialState to loadCurrentState and update related references. r=nsharpley
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1952061
• 🌟Keji Bakare
  • Bug 2006572 – fix  right tab name and icon shift when the Split View is selected
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2006572
  • Bug 2025287 – Hide “Open Link in Split View” menu option for pinned tabs.
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2025287
• 🌟Hailia
  • Bug 2016934 – Update copied profile header with typographic quotes r?jhirsch
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2016934
• geppy
  • Bug 1767617 – Rename –theme-graphs-* CSS variables r?nchevobbe
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1767617
• 🌟Itoro James
  • Bug 1936929 – Document the ::%shadow% and ::%document% anchor selector tokens r?nsharpley,hanna_a
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1936929
• 🌟konyhéa
  • Bug 1856191 – don’t restrict the sidebar width so much (better support non-English locales)
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1856191
• konyhéa
  • Bug 1876108 – add hairline separator between synced tabs device lists in firefox view
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1876108
  • Bug 1891970 – Update firefoxview breakpoint to 950px
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1891970
  • Bug 2014334 – add outline to tab-split-view-wrapper when used as a drag group target
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2014334
• 🌟Noble Chinonso
  • Bug 1945835 – Add timestamp display to synced tabs list
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1945835
  • Bug 1953621 – Fix command property type in SidebarStateProps from boolean to string
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1953621
  • Bug 2019235 – Disable Move to Start/End for split view tabs based on tab position
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2019235
  • Bug 2025701 – Fix mismatched closing tag in syncedtabs-tab-list.mjs itemTemplate
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2025701
• Knot False
  • Bug 1773932 – Remove nsIScriptableUnicodeConverter from services/common/utils.sys.mjs. r=skhamis,markh
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1773932
• 🌟Pranjali Srivastava
  • Bug 1874155 Remove browser.firefox-view
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1874155
  • Bug 2009917 – Added proper spacing
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2009917
• 🌟Chukwuka Rosemary
  • Bug 1846829 – Remove the max-history-rows pref used in Fx View
    • https://bugzilla.mozilla.org/show_bug.cgi?id=1846829
• 🌟Sameeksha
  • Bug 2008178 – Add accessible name to ConfirmDialog using aria-labelledby. r=thecount
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2008178
  • Bug 2021421 – Remove redundant lazy preference getters in sidebar-pins-promo.mjs
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2021421
• kofoworola shonuyi
  • Bug 2019901 : Remove sidebar-ongoing-animations attribute from sidebarMain after animation reset.
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2019901
• 🌟Oluwatobi
  • Bug 2019936 – Remove preference configuration for the IE importer feature. r=nsharpley,kcochrane,mconley
    • https://bugzilla.mozilla.org/show_bug.cgi?id=2019936

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• Fixed a long-standing issue where extension paths stored in extensions.json (and addonStartup.json.lz4) became incorrect after restoring a Firefox profile to a different location and causing all previously installed add-ons to fail to load  – Bug 1429838

DevTools

• geppy renamed some of our CSS variables to be more explicit (#1767617)
• Sebastian Zartner [:sebo] move the :visited pseudo-class to element-specific section in the Inspector pseudo-class (:hov) panel (#2017985)
• Ben improved the RDM “Add Custom Device” form by making sure it worked for any kind of locale (#1705177)
• Chris Vander Linden continued his work to migrate files to use actual private fields (#2022400, #2022402, #2022403, #2022405, #2022406, #2022407)
• Dana Keeler (she/her) [:keeler] added a distinct icon to Netmonitor requests when a request uses a certificate issued by a third-party root (#2022693)
  • 
  • https://snipboard.io/QtwV2R.jpg
• Nicolas Chevobbe [:nchevobbe] added a <global> node on objects which are not from the top-level debugged page (it’s always visible in the browser console/browser toolbox) (#1962343)
  • 
  • https://snipboard.io/uJg2vN.jpg
• Nicolas Chevobbe [:nchevobbe] added possible anchor names to the autocomplete for the position-anchor property, as well as for the anchor() and anchor-size() functions (#1903278, #2023114, #2023576)
  • 
  • https://snipboard.io/t6QUBF.jpg
• Nicolas Chevobbe [:nchevobbe] added proper autocomplete (including things like interpolation/color space) for linear-gradient() (and repeating-linear-gradient())  (#2025761)
  • 
  • https://snipboard.io/1LNp26.jpg
• Leo McArdle [:leo] fixed an issue in the Inspector Fonts panel Weight input (#1578023), and made sure we properly round displayed values (#1465026, #1578022, #2013940)
• Nicolas Chevobbe [:nchevobbe] made the animation speed drop down to be always visible in the animations panel (#1995485)
  • it now impacts all the animations in the page, not only the ones in the subtree of the selected node
• Julian Descottes [:jdescottes] fixed frequent DevTools crashes by avoiding to access properties on remote proxy windows in various places (#2026134)

WebDriver

• Khalid AlHaddad refactored the WebDriver BiDi tests by moving the “wait_for_bidi_events” helper to a fixture.
• Henrik Skupin splitted fixtures and helpers for WebDriver classic and BiDi into protocol-specific folders and improved Marionette’s window manipulation logic for Wayland headless/headful jobs.
• Henrik Skupin added support for “altitudeAngle” and “azimuthAngle” in pointer actions of subtype “touch” to both Marionette and WebDriver BiDi.
• Julian Descottes fixed browsingContext.reload to properly reload iframes and simulate more accurately a user-initiated reload.
• Alexandra Borovova updated “log.entryAdded” events to include top-most frame of the stacktrace for all types of Console APIs.
• Alexandra Borovova updated the handling of shutdown requests to make sure that all active downloads are canceled before to not block the actual browser shutdown.

Lint, Docs and Workflow

• Globals handling within VS Code (and maybe other editors) has been improved to avoid caching globals when the source file for the globals has been updated.
  • The main impact of this is that when changing globals in head.js files, VS Code’S ESLint reporting will see the changes when you have the test files open that use the head.js file.

New Tab Page

• Irene Ni updated the Shortcuts UI to Nova, refreshing about:newtab shortcuts with the new design system and improved focus states.
• Irene Ni made it possible to increase shortcuts row count from 8 to 10 for Nova, which will let users pin two more sites per row without scrolling.
• Hanna Alemu built the UI code for asrouter-newtab-message, enabling ASRouter-driven new tab messages controlled via remote config.
• Dre fixed some New Tab keyboard navigation bugs, restoring predictable Tab/Arrow traversal across tiles, cards, and the customization controls.
• Nathan Barrett fixed a persistence bug where Weather, Shortcuts, and Recommended Stories couldn’t be disabled after restart while New Tab was focused, ensuring section toggles reliably save and apply across restarts.
• Sameeksha added an accessible name to the ‘Delete from History’ dialog in Recent Activity, allowing screen readers to announce the dialog title and purpose.
• Maxx Crawford labeled the Detailed view menu button for accessibility, making the control discoverable to assistive tech.
• Maxx Crawford made the ‘See full forecast’ link keyboard-focusable in Detailed view, improving navigation without a mouse.
• Reem Hamoui conveyed high/low temperatures to screen readers in the Detailed view, exposing key weather info non-visually.
• Reem Hamoui added alternative text for hourly forecast graphics, enabling meaningful announcements instead of unlabeled images.
• Maxx Crawford fixed fluent-dom handling so a br element is preserved in newtab-topsites-add-shortcut-label, restoring the intended line break in the Add Shortcut label.

Search and Urlbar

• Dao and Moritz worked on follow ups and fixed several bugs related to the new search bar implementation, which shipped in Fx 149 (2026248, 2023611, 2025746, 2022159, 2022809, 2023656, 2023141)
• Mandy added a new `hasBeenUsed` attribute to search engines to enable better messaging system targeting (2024078)
• Mandy also added a new telemetry category for when search mode is activated via a feature callout (2018806)
• Drew and Daisuke are continuing their work on making Nova updates to the urlbar (2019165)
• Dale fixed two bugs related to the new Unified Trust Panel (2019928, 2013044)
• Florian used Claude to fix intermittent bugs related to urlbar and search telemetry (2009767, 2024301)
• James fixed a high frequency intermittent test failure in the urlbar code (2001962)
• Marco fixed a high frequency intermittent test failure in the places database code (1981199)

Tab Groups

DJ is adding the ability to copy all URLs from the tabs in a tab group 1984338 – Add a way to share/send/copy all tabs urls from a given tab group

Highlights

• Thanks to overholt, macOS Nightly now has support for sharing the current tab’s URL via QR Code (Right-click tab, Share > Generate QR Code). This is held to Nightly for now.
  • 
• Scott Downe fixed an issue where newtab background GIFs could max out RAM while idle in the background by throttling animated background decoding on backgrounded tabs. This fix is going out in Firefox 150.
• Special thanks to volunteer contributor 1justinpeter who just added speed unit conversion support to the AwesomeBar!
  • You can try it in Nightly – try 1000 km/h to m/s
    • 
  • This is tentatively slated to go out in Firefox 150
• New Tab Sections have been enabled by default in Canada!
  • 

Friends of the Firefox team

Resolved bugs (excluding employees)

Volunteers that fixed more than one bug

• Chris Vander Linden
• Itiel
• Justin Peter
• Khalid AlHaddad
• Mauro V [:cheff]
• Sam Johnson
• Sebastian Zartner [:sebo]

New contributors (🌟 = first patch)

•  Mohammed Abdullah: screenshot command crops image after 10000px height
•  Jocsan: Profile delete page title should enclose profile name in quotes
• 🌟 karan68: [dialog] ‘X’ icon buttons are missing labels
•  Knot False: Replace KeywordUtils use of nsIScriptableUnicodeConverter with Services.textToSubURI.ConvertAndEscape
• 🌟 Pushkar Singh: Remove unused devtools.inspector.remote pref
• 🌟 MUTHUSRIHEMADHARSHINI: Card images do not have an alt attribute
•  Sukhmeet[:sukh]: firefox forgets open tabs depending on window close order
• 🌟 Alex Reisner: Create a preference to disable the drag-and-drop method of creating tab groups
• 🌟 torrenceb90: Remove unused devtools.target-switching.server.enabled pref
• 🌟 baris: Button does not programmatically indicate that it opens a dialog (Customize button)

Project Updates

Add-ons / Web Extensions

WebExtensions Framework

• Fixed a structuredClone regression in the MV2 userScripts sandbox, bringing it in line with the fix already applied to content scripts and MV3 userScripts sandboxes, fix applied in Nightly 150 and uplifted to Beta 149 – Bug 2020773
• Fixed a tab crash triggered by calling Document.parseHTMLUnsafe() from a browser extension content script (due to an assertion failure hit because parseHTMLUnsafe was wrongly trying to create a document that belongs to the expanded privileged principal that originated the call). The changes applied is now making sure parseHTMLUnsafe will use the webpage document’s principal (and prevent the crash as a side effect of that) – Bug 1912587
• Fixed a regression where the load event on about:blank iframes would not fire when a content script injected a style element (regressed in Firefox 148 as a side effect of the changes applied by Bug 543435, fix landed in Nightly 140 and uplifted to Beta 149 and Release 148) – Bug 2020300
  • Thanks to Vincent Villa for promptly investigating and fixing this regression!

WebExtension APIs

• As part of followups related to the work to allow action.openPopup calls without user activation, action.openPopup() will reject the requests when another panel, context menu, doorhanger, or notification is already open in the window – Bug 2022281
• As part of followups to the work in support of the splitView mode support introduced in the tabs API, tabs.move() has been tweaked to correctly return all specified tabs moved in a split view – Bug 2022372

Addon Manager & about:addons

• Fixed a rendering regression where the context menu on about:addons cards would appear with a transparent background at non-default zoom levels – Bug 2006926
  • Thanks to Botond Ballo for investigating and fixing this small rendering regression!

DevTools

• Chris Vander Linden moved the SearchInFileBar component to a shared folder in (#2019256, #2020518)
• Chris Vander Linden made a few Netmonitor file use proper private properties (#2021639, #2021640, #2021641, #2021642, #2021643, #2021644, #2021645)
• Mohammed Abdullah refactored screenshot dimension handling to use shared logic from ScreenshotsUtils.sys.mjs (#1942439)
• Lorenz A fixed an issue in the Flexbox Layout pane regarding base size when flex-basis was set from the flex shorthand (#1939289)
• Oriol Brufau [:Oriol] improved one of our object test (#2021445)
• Sebastian Zartner [:sebo] added a new Element-specific pseudo-classes section in the pseudo-class panel and added support for the new :open pseudo class (#2014442)
  • 
• Simon Farre [:sfarre] made it so Reporting API requests are now visible in Netmonitor (#2013043)
• Leo McArdle [:leo] fixed the Network request panel so it would show POST data even before the request was finished (#2014623)
• Leo McArdle [:leo] fixed a couple issues with the Inspector Fonts panel inputs (#2013910, #2013904)
• Julian Descottes [:jdescottes] updated the device list in Responsive Device Mode to include recent phones and tablets (#1982802)

WebDriver

• Khalid AlHaddad contributed over the past two weeks by adding a test for correct viewport dimensions on new top-level browsing contexts, improving WebDriver tests with global asyncio markers and a timeout multiplier for a better stability of slow running builds, and introducing a fixture to remove webextensions installed during a test. Thank’s a lot!
• James Teh added Marionette-prefixed commands to query extended accessibility properties and traverse the accessibility tree using UUID-identified nodes.
• Jonathan Moss updated the marionette-integration test manifest files so all tests now run as part of the OS integration CI jobs.
• Alexandra Borovova fixed a regression when prompts opened with WebDriver Classic were automatically closed by default when the `moz:debuggerAddress` capability was passed, which is still a common pattern for Selenium.
• Alexandra Borovova fixed the download events that were triggered by the requests with the `Content-Dispostion` header opened in the new tab to be linked to a navigation.
• Alexandra Borovova updated the logic to not send the “log.entryAdded” events for console APIs that don’t use the printer (e.g., `console.time` or `console.clear`).
• Henrik Skupin fixed an issue in the browsingContext.locateNodes command where the root element was not returned when using a CSS selector.
• Henrik Skupin simplified the logic for Marionette commands managing window state, size, and position to improve stability.
• Julian Descottes fixed the support of non-utf8 headers for various network module commands.
• Julian Descottes fixed a bug with keepalive requests which could still be sent after setting the network conditions to “offline”.
• Julian Descottes fixed a race condition which could lead parallel calls to browsingContext.setViewport to timeout.

Lint, Docs and Workflow

• Mossop has replaced most instances of ContentTask.spawn with SpecialPowers.spawn.
  • There is a lint rule to prevent further uses.
  • Feel free to help clean up existing uses if you have any.
• https://arewemozsrcyet.com/ is live and in the middle of being moved to a mozilla repo, bugs / comments can go to https://bugzilla.mozilla.org/show_bug.cgi?id=2014746
  • 

New Tab Page

• Luca Greco fixed an issue where the new tab page was broken for users who had moved their profile to a new directory. Special shout-out to Scott for driving that one over the line and getting the fix uplifted to Beta!
• baris updated a button so that it indicated that it opens a dialog (Customize button) by adding aria-haspopup=”dialog” and focus management so screen readers announce the Personalize dialog correctly.
• Maxx Crawford added the first version of a refined grid system for Nova, introducing column-based container queries and CSS tokens for more consistent responsive New Tab layouts. This is currently off by default.
• Maxx Crawford updated Widgets components to use parent grid columns so cards align to the new Nova grid across breakpoints without layout jumps.
• Mike Conley enabled the pref to communicate with MARS over OHTTP by default so New Tab network calls use OHTTP by default, reducing IP exposure for all channels. This was already enabled on Beta and Release via Nimbus, but this patch is the pref flip that will ride the trains.
• Mike Conley added a train-hoppable asrouter-newtab-message external component for inline messaging to let us update New Tab inline messages via Remote Settings without a full Firefox update. The OMC team will take over building out the actual UI for the new message surface.
• Nathan Barrett landed sections layout support for Nova, to refine section spacing and ordering using the new grid for a cleaner, denser above-the-fold.
• Maxx Crawford fixed “Weather data is not available right now message” begin shown on the Weather widget by correcting gating so the Weather widget fetches and renders data reliably on v150.
• Maxx Crawford resolved an issue where experiments could accidentally override weather preferences set by the user
• Nina Pypchenko [:nina-py] aligned the newtab devtools button to match the Personalize button to improve visual consistency and discoverability of the DevTools toggle.

Search

• Marco worked on replacing ContentTask.spawn in various tests @ 2023131, 2023134
• Dale worked on several TrustPanel UX fixes @ 2017369, 2017376
• Daisuke fixed issue with SwitchTab results with no title @ 2020341
• Moritz worked on several telemetry issues relating to the new search bar 2021927
• Moritz fixed the unified search button having no focus border @ 2023656
• Dao added support for middle clicking to search in the unified search menu @ 2011220

Smart Window

• “Beta” badges 2017667
  • 
• Added AI Controls integration, supporting the blocked state (2010599)
  • 
• Added more user choice with split memory generation (2017428)
  • 
• Added chat search in Firefox View (2009070)
• Follow-up prompts now persist across tab switches (2019696)
• Conversation starter prompts now update with the foregrounded tab (2013657)
• Current tab context is now removable (2018802)
• Keyboard fixes for smartbar input (2019556 2017939 2015090)
• Show sign in button in chat if signed out (2015720)

Storybook/Reusable Components/Acorn Design System

• Tim Giles fixed some issues with panel-list using popover:
  • A macOS issue where keyboard events went to the wrong <moz-select>Bug 2017668
  • Scrolling now dismisses an open panel-listBug 2018563
• akulyk updated the panel-list variant of moz-select to use role=”combobox”, improving screen reader semantics and keyboard navigation consistency.
• Dustin Whisman updated the moz- widgets CSS to pass use-design-tokens:
  • panel-list, moz-input-*, moz-select, moz-toggle, moz-visual-picker, moz-message-bar, moz-five-star, and moz-reorderable-list
• Dustin Whisman updated some design token names for consistency (Bug 2013342):
  • –font-size-heading-* now a font-size variant (was –heading-font-size)
  • –card-border-color, –card-box-shadow, –card-box-shadow-hover, –popup-box-shadow, –tab-box-shadow (were nested as variants previously and now are under their component name)

UX Fundamentals

• Added keyboard autofocus to the “Try Again” button in Felt Privacy error pages so users who land on an error page can immediately press enter to retry. (2021447)
• Added keyboard access keys to the three primary error page buttons: G (Go Back), T (Try Again), and P (Proceed to Site). (404501)
• In progress: refactoring net error illustrations into a shared object and adding alt text so assistive technology can read out meaningful descriptions. (2022033)
• In progress: adding improved messaging to the file-not-found error page. (2018850)
• In progress: restoring the error page for Work Offline mode so users see messaging that accurately reflects that they’re in Offline mode, not that there’s a network problem. (