Highlights

• Here are some big-ticket volunteer contributions this week:
  • Thank you to volunteer contributor Cornelius, who made console evaluation able to re-declare let and const variables in our DevTools!
  • Thank you to F3tch, who landed several patches to allow setting of camera and microphone permissions, reject zero-sized screenshots, and add a vendor-specific WebDriver BiDi command for listing installed extensions, as well as update cookie test expirations.
  • Thank you to SMRehan, who landed a (disabled by default) mode that lets Picture-in-Picture open when the browsing window is occluded (as opposed to when changing tabs).
    • This can be tested by setting media.videocontrols.picture-in-picture.enable-when-occluded.enabled to true
  • In Nightly 160, we have enabled the playback speed feature for Picture-in-Picture by default:
  • Thank you to volunteer contributor Simon Rosen for the bulk of the initial work on this!
• The custom wallpaper library for newtab is now available, starting in Firefox 158, so you can now store multiple custom wallpapers:

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
• Amadi
• any1here
• Duncan McIntosh [:dmcintosh]
• f3tch [:f3tchcodes]
• ianlewisuk1
• Ivan Smagin
• Khalid AlHaddad
• Logan Rosen [:Logan]
• Mayank Bansal
• Vir Patel

New contributors (🌟 = first patch)

• Ahmed ElGendy: Add a `(inline-)grid-lanes` badge in the markup view for element with display: (inline-)grid-lanes
• Mubashshir: Extension icon missing in old sidebar switcher
• Anton Bershanskyi: Introduce browser.runtime.PlatformArch.ARM64
• Amadi:
  • Clicking the New Tab button does not show pressed appearance with vertical tabs
  • Not localized search matches in Devtools
  • Remove unused WebsiteFilter module getter from browser.js
• Caleb Pickard: New sidebar revision does not have “By Most Visited” as a sort option for History
• Daniel mungai chege: Add autocomplete for CSS random()
• dchen705: syntax and handling of async runtime.onMessage listeners is confusing
• Diego: Pressing ctrl+shift+numpad1 causes tab to be moved to end of tab list regardless of NumLock
• f3tch [:f3tchcodes]:
  • “WebDriver:TakeScreenshot” doens’t throw “unable to capture screen” error if height or width of captured image is 0
  • Increase expiry date range for network cookie tests
  • [wdspec] ValueError: “list.remove(x): x not in list” for “self.event_listeners[name].remove(fn)”
  • [firefox-devtools-mcp] Support webextensions.moz:listExtensions command in WebDriver BiDi
  • Allow “permissions.setPermission” and “WebDriver:SetPermission” to set camera and microphone permissions
• Ole Baumann [:darkintaqt]:
  • 🌟 Drop the redundant level from UrlbarUtils.getBackspaceBlock’s return value
• ianlewisuk1:
  • Add Nova icons for Firefox :: Messaging System
  • The corrupt_file telemetry metric counts session files with an incompatible format version as healthy files
• Jakub Stasiak [:jstasiak]: Early WebSocket messages can be missing in the Network tab
• Jaron: Show the remote control stripe on the address bar only
• 🌟 Lavindeep: Subprocess fcntl binding is not variadic, causing incorrect pipe flags and possible native-host launch failures on Apple silicon
• 🌟 Sho Sakuma: Fix WP_WIN and WP_MACOSX typos in LaunchChild’s #endif comments
• Raúl: Remove dead PanelUI-fxa-menu-setup-sync-container from the account menu
• 🌟 Jason Salerno: Remove the unused tooltip attribute from the urlbar view markup
• Ivan Smagin:
  • Improve pref-handling in xpcshell test ‘test_ext_contentscript_module_import.js’
  • Add test for unknown content dialog for downloads with a mimetype that doesn’t have an associated file extension
• Nazeer Ahmed Shaikh: Instrumentation tests on artifact builds do not check `object` metric schema
• Vir Patel:
  • Make DisplayMenuBar pass a string to runOncePerModification
  • Handle the “cleared” perm-changed notification in the permission exceptions dialogs
• Valerie Racine (:v-racine): The corrupt_file telemetry metric counts unrecognised session file read errors as healthy files
• 🌟 Yeet: Saved tab groups not actually saved if browser crashes

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• Removed the colorway migration code and the about:addons UI informing users about colorways on AMO – Bug 1990883
  • Thanks to Jason Birchall (from AMO engineering) for collaborating with us on this.
• As part of about:addons Nova restyling followups
  • Parameterized the built-in theme preview images, and fixed the default theme previews rendering with the wrong colors when about:addons uses the opposite color scheme (regression introduced and fixed within Firefox 158) – Bug 2070289 / Bug 2074428
    • Thanks to Emilio Cobos Álvarez for driving the theme preview parameterization.
  • Fixed the Nova theme preview gradients being mirrored in RTL locales – Bug 2073245
  • Hid the (non-localized) theme card descriptions in the about:addons themes list view, fixed in Firefox 158 and uplifted to Firefox 157 – Bug 2071337
  • Fixed the per-add-on-card message bar styling in about:addons to better match the Nova designs – Bug 2079672
• Avoided redundant AMO metadata update checks when the app locale is unchanged – Bug 2052032
• Added options to AddonManager.getInstallForURL to validate the add-on type, id and/or version before installing – Bug 1973071
• Dictionary add-ons are now required to be signed, starting in Firefox 160 – Bug 1753276

WebExtensions Framework

• As part of work to refactor about:newtab built-in widgets in their own privileged extensions, allowed about:newtab pages to load extension pages as subframes without listing them in web_accessible_resources – Bug 2070235
• Improved pref handling in the test_ext_contentscript_module_import.js xpcshell test by using pref_set – Bug 1986064
  • Thanks to Ivan Smagin for the cleanup in the content script module import test.

WebExtension APIs

• Fixed publicSuffix.isKnownSuffix to throw for invalid host names, in line with the API proposal, MDN and Chromium – Bug 2066620
• Added runtime.getVersion() – Bug 1992418
  • Thanks to Carlos for implementing the new runtime API method.
• Introduced runtime.PlatformArch.ARM64 (replacing AARCH64) to match Chromium, landing in Firefox 160 – Bug 2080310
  • Thanks to Anton Bershanskyi for the runtime.PlatformArch rename.
• Stopped exposing non-browser windows in windows.onFocusChanged, fixing a “gBrowserInit is undefined” error hit through tabs.query – Bug 1634240
• Fixed sessions.forgetClosedTab() forgetting the wrong tab when the window has a closed tab group – Bug 2076684
  • Thanks to Dão Gottwald for investigating and fixing this bug hit by the sessions API.
• Fixed extension menu items being unreachable by accesskey, including items with Chinese, Japanese or Korean labels – Bug 2074182 / Bug 2075142
  • Thanks to Dão Gottwald for driving these menus accesskey fixes.
• Added a warning when sendResponse is called by an async runtime.onMessage listener, landing in Firefox 160 – Bug 1877223
  • Thanks to dchen705 for the runtime.onMessage warning.

DevTools

External contributions

• Jakub Stasiak fixed an issue in the Netmonitor where we could miss early WebSocket messages (#1719394)
• Amadi localized string in Debugger search panel (#2035151)
• Daniel mungai chege added autocomplete in the Rules view for the random() function (#2072513)
• Ahmed ElGendy added (inline-)grid-lanes badges in the markup view for element with display: (inline-)grid-lanes (#2076779)
• Khalid AlHaddad removed an unused argument in the KeyShortcuts constructor (#1979386)

Team/Project Update

• Florian Quèze [:florian] made DevTools splitters keyboard accessible (#1860733) and fixed numerous other accessibility issues across the toolbox (#2071228, #2071230, #2071232, #2071233, #2071236, #2075809, #2075820)
• Leo McArdle [:leo] started modernizing the DevTools Settings panel (#2072146, #2072216, #2074393, #2074399)
• Nicolas Chevobbe [:nchevobbe] Handle percentage in CSS explainers tooltip (#2041621) and show the tooltip for single non-pixels values (#2074405, #2064400)

• • (pref: devtools.inspector.css-explainers)
• Hubert Boma Manilla (:bomsy) is working on adding support for speculation rules in DevTools. Prefetched requests can now be identified in the Netmonitor (#2077519) and he plans to add more information about speculations rules in a dedicated tab in the Application panel (#2077995, #2078853)

WebDriver

• Beatriz Rizental improved the Marionette harness to accept multiple –tag arguments similar to other in-tree harnesses.
• Khalid AlHaddad improved the PollPromise to throw an error by default and not only log a warning when it times out.
• Alexandra Borovova added support for the imageSize argument to the browsingContext.captureScreenshot command, which allows clients to specify the maximum size of the resulting screenshot image.
• Alexandra Borovova added support for the destinationFolder argument to the browsingContext.startScreencast command, which allows clients to choose the folder where the recorded video file is saved.
• Alexandra Borovova implemented the support for the prefers-color-scheme parameter in the emulation.setMediaFeaturesOverride command, which lets clients emulate dark or light mode on a website.
• Henrik Skupin improved the handling of recommended preferences for automation to use the default branch, preventing them from leaking into subsequent Firefox sessions.
• Henrik Skupin fixed a bug where accepted server sockets still had Nagle’s algorithm enabled, causing up to 40ms delays for back-to-back writes on Linux.
• Henrik Skupin improved geckodriver’s shutdown handling by waiting for Firefox’s hang monitor to terminate hung processes before force-killing them.
• Henrik Skupin added a temporary workaround to prevent Glean from causing shutdown hangs for short-lived Firefox processes.
• Holger Benl added machine-readable CDDL for all Firefox WebDriver BiDi vendor extensions (“moz:” commands, events, parameters, capabilities…).
• Privileged context support was added to browsingContext.locateNodes and input.performActions by Holger Benl, and to browsingContext.captureScreenshot by Julian Descottes.
• Julian Descottes fixed the network.getData command to handle 304 – Not Modified responses with no timeouts.

Fluent

• Shout out to flod who’s started to chip away again at migrating .properties files to Fluent!
  • For the first time since we started tracking, there are fewer than 4000 .properties strings in the Firefox source code!

Migration Improvements

• spohl is working on a stack of patches that’ll update the migration workflow for macOS 27 to reduce the number of data access permission warnings that users see

New Tab Page

• We’re testing a few different layout variations in the wild – one of them is a few different takes on “spaces”:

• The MCAB search input is currently being deployed to a small population in the wild to see how it works / is received

• A train-hop is scheduled to be deployed this week which should make widgets available for all users (though for most users, these will be disabled by default – they’ll be available to enable in the customize panel).

• Reem Hamoui removed the Enzyme/Karma test infrastructure from the New Tab Page, which is a CI/dev tooling change with no direct runtime user impact but should reduce test maintenance and flakiness for future user-facing fixes.
• Jack Brown switched New Tab message visibility checks to an IntersectionObserver so messages below the fold are no longer marked as activeNotifications, preventing offscreen messages from being targeted and avoiding unnecessary JS evaluation when not visible.
• Jack Brown cleared activeNotification targeting when navigating away from about:newtab so message targeting no longer persists after leaving the page, preventing carry‑over interactions and incorrect metrics attribution.
• akulyk [a11y] fixed dialog focus containment on the New Tab Page by enforcing a focus trap and proper Tab/Shift-Tab handling, restoring expected keyboard and screenreader workflows for modal dialogs.
• Scott fixed pocket.click and topsite.click to trigger context menus correctly, restoring right-click/long-press context menus on Pocket tiles and Top Sites so users can access actions like open-in-new-window and remove.
• Maxx Crawford updated per-widget Jest fixtures for Stocks, Privacy and Picture of the Day to omit the widgets.enabled flag in test setups Per-widget Jest fixtures for Stocks, Privacy and Picture of the Day omit widgets.enabled, which aligns test fixtures with runtime enablement behavior and reduces CI flakes and regression risk for those widgets; there is no runtime UI change for end users but widget rendering tests should be more reliable.
• Maxx Crawford removed the Sports widget from the New Tab Page and widget picker, which directly removes sports headline/cards from users’ NTP experience (users who had Sports selected will no longer see it) and slightly reduces client-side DOM/paint work and widget surface area for future NTP changes. It also removed about 1MB of image / video assets from the omni.ja / newtab XPI.
• Maxx Crawford added region/locales dynamic control for the Weather widget, allowing users to change the Weather card’s region/locale on New Tab so forecasts and localized labels update immediately.
• Herraj Luhano updated the POTD API contract to return the previous day’s POTD, enabling the New Tab image module to fetch and display yesterday’s Picture of the Day to avoid empty or stale image slots.
• Nina Pypchenko [:nina-py] re-ordered New Tab settings in about:preferences, improving discoverability by placing New Tab controls in a more consistent, prominent location for users managing Start Page options.
• Dre standardized context menu button UI across all widgets, unifying markup, CSS variables and ARIA to make context-menu hit areas and keyboard focus consistent across widget surfaces.
• Dre standardized header typography across all widgets, aligning font sizes, line-heights and tokens so widget headers render consistently on New Tab pages.
• Maxx Crawford updated WallpaperFeatureHighlight to allow for alternate strings to be injected so the New Tab wallpaper feature highlight UI can show injected copy variants (for localization or experiments), which directly changes the text users see in the wallpaper picker/highlight flow and should be monitored for clarification/regression in impressions and CTA click rates.
• David Durfee landed a meta change to enable score-based selection for sponsored tiles in the New Tab experiment, which replaces the previous selection heuristic with a ranking/scoring pipeline so experiment cohorts may see different sponsored tiles on New Tab (affects which ads/content are shown, sponsored impressions/CTR, and A/B metrics for desktop and mobile New Tab surfaces).
• Nina Pypchenko renamed the Stocks widget to “Finance” on the New Tab Page, updating the activity-stream UI/i18n label users see in the widget header.
• Brendan Birdsong adjusted the newtab score-based selection to sum day counts from remote-settings config, which can change which cards/tiles are selected and their ordering for users depending on remote config values.
• Scott Downe removed the discoverystream.optIn-region-weather-config pref from newtab, a config cleanup that does not change runtime New Tab UI or user-visible weather opt-in behavior.
• Irene Ni normalized the layout_name value in New Tab DSCard impression telemetry, ensuring consistent impression records for analytics and A/B experiments without altering the UI seen by users.
• Scott Downe removed the telemetry.structuredIngestion.endpoint pref from newtab, removing a pref-based override for structured-ingestion endpoints (affects developer/testing overrides, not regular user behavior).
• Irene Ni removed unused ImpressionStats dispatches from New Tab DSCard clicks, eliminating redundant telemetry dispatches on DSCard click paths with no UI change.
• Irene Ni normalized Top Sites telemetry keys to their Glean extra names, stabilizing telemetry naming for Top Sites without changing user-visible behavior.
• Dre fixed a slight flash when reusing a previously uploaded wallpaper in the New Tab Page, removing a visible flicker for users who set custom uploaded wallpapers.
• Maxx Crawford added a debug pref/setting to revert region controls, enabling targeted rollbacks/enabled testing for affected-region UI behaviors when the pref is toggled.
• Jared Wein fixed TypeScript errors in newtab/lib blocking inclusion in newtab’s tsconfig.json, resolving a build/tooling blocker (developer-only change; no direct user impact).
• Irene Ni made the Spaces arrow-buttons variant background panel occupy the full page height on the New Tab Page, removing a visual gap and ensuring arrow controls stay aligned with page scroll.
• Alexandre Hanot fixed Ads client initialization on Firefox 157 and older so the Ads client now initializes instead of throwing errors on legacy builds, restoring ad content on affected users’ New Tab Pages.
• Dre prevented the Clocks widget menu button from overlapping clocks on hover by adjusting z-index and hover layout, restoring visibility and correct hit targets on the New Tab Page.
• Irene Ni enabled a widget in the first content position of New Tab sections, updating New Tab rendering logic so a prioritized widget slot is populated in the first content position and becomes visible by default to users.
• Jared Wein enabled type checking for newtab/lib with exception for failing files, adding incremental static-analysis/CI checks to catch regressions in newtab code without changing UI behavior today.
• Maxx Crawford set default enabled value to false for all existing widgets, changing widget metadata/prefs so existing widgets are opt-in and will no longer render for users unless explicitly enabled.
• David Durfee added differential privacy noise to scores in newtab score-based selection, anonymizing per-user signals which will alter ranking/discovery behavior on the New Tab page while underscoring privacy guarantees.
• Brendan Birdsong moved newtab score storage to PersistentCache, persisting scores across sessions and reducing recompute/lookup latency so personalized selections are more stable and faster to load.
• Jared Wein fixed more newtab/lib TypeScript errors so 11 more files can be type-checked, enabling type-checking across newtab/lib (11 files) and lowering regression risk for New Tab Page behavior.
• Dre used useWidgetTelemetry in the Weather widget to standardize telemetry for the Weather widget (New Tab Page), improving diagnostic signals that help us find and fix user-facing widget issues faster.
• Maxx Crawford turned off all New Tab widgets in automation with one pref, allowing automation to run with widgets disabled to reduce flakiness in tests that interact with New Tab UI.
• Dre updated the Focus Timer widget to use useWidgetTelemetry, so Focus Timer telemetry now respects widget-level prefs and will avoid sending unguarded pings—privacy impact only, no UI change.
• Nina Pypchenko [:nina-py] fixed transparent New Tab dialogs when the train-hop is applied to Firefox 158 and 159, restoring dialog opacity/CSS so newtab overlays are readable again when train-hop is enabled on those releases.

Picture-in-Picture

• kpatenio fixed a bug on Windows and Linux where clicking a previous control overrides the Space play/pause shortcut.
• kpatenio landed a few patches to make keyboard navigation better when the playback speed control is enabled (Bug 2055070, Bug 2074319).
• As of Nightly 159, the PiP player UI has been updated for Nova. Aside from being visually consistent with Nova, scrubbers and settings panels now have better contrast on High Contrast Mode.

Search and Urlbar

Urlbar

• Dao landed a patch to show the “Search tabs” keyboard shortcut in the search mode switcher menu: 2078113

• Logan Rosen changed the Accel+Shift+A shortcut from the Add-ons Manager to Search Tabs: 1666654. Dao followed up by notifying people who used the old shortcut that it moved and revised the wording of that message: 2077823, 2079208
• James added an option to skip the menu when tabbing through the address bar, in both the address bar and the preferences page: 2064708, 2068609
• Dao fixed a bug so that entering an address in search mode now navigates to that URL: 2036347
• Dao fixed two urlbar.bounce telemetry bugs: 2069403, 2076827
• Caleb fixed a bug where the address bar results dropdown covered the calculator tail150 game: 2077358
• Daisuke fixed a bug where search terms in the address bar moved when pressing Enter or when edited: 2074921
• Dao fixed the search engine button being cut off in the Search dropdown with Nova enabled: 2074871
• Daisuke fixed the search switcher’s active button color being too strong with low text contrast in Nova: 2068504
• Emilio fixed the Quick Actions background button missing in the Light theme on Ubuntu in Nova: 2076191
• Moritz continued with MCAB (multi-context address bar) follow-on work: 2078231, 2078658, 2078672.
• Moritz also enabled TypeScript type checking for UrlbarView and UrlbarBaseInput: 2077545, 2077543
• Dao significantly improved the address bar docs, including how to add a new search surface end to end, how results and providers work across the process boundary, and how to debug and log the address bar:

 Search

• Caleb fixed a bug where the address bar swallowed the first character typed into it if you typed too quickly: 1953361
• Mark continued working on the new search config, search-config-v3: 2063279, 2063264

Places

• Dao fixed a bug where the bookmark creation/editing panel had no keyboard shortcut mnemonic for the Save button: 1877510

Storybook/Reusable Components/Acorn Design System

• Dialogs in about: pages now match Nova designs more closely
• Moz- widgets should now have types found when querying the element with document.querySelector(“moz-button”) and TS is configured
• A11y fixes for profiles dialog, page nav keyboard handling (no longer steals Ctrl+arrows)

Highlights

• Firefox 155 just released! That’s the first release that went through the full 2-week release cycle process.
• The WebExtensions team added a new backgrounds_area theme property so themes can explicitly control whether background images apply to the whole window or only the top toolbars
  • Thanks to Emilio for the new theme property to control background image placement!
  • This is targeting Firefox 156, and developer documentation will be added to MDN soon.
• The multi-context address bar for New Tab has been enabled in Nightly!

• • There are a number of known bugs to address before this can ride. We’re tentatively aiming to have this release sometime in Q4.
  • Notice an issue with it? File a bug here!
• Volunteer contributor Andrew fixed a white flash for the New Tab page on startup for users that have dark mode enabled by default.
• The DevTools team has made it possible to inspect and edit stylesheets from within the JavaScript Debugger pane.

• • The feature can also be enabled from the experimental section in the devtools settings panel, or by setting devtools.debugger.features.stylesheets-in-debugger to true in about:config.

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

Volunteers that fixed more than one bug

• :Benjamin Peterson
• ExplodingJoysticks
• Gopalarathnam Venkatesan
• Khalid AlHaddad
• Lukáš Lipinský
• Chris Van Linden

New contributors (🌟 = first patch)

• 🌟 Amadi: Update comments that point at the removed openUILinkIn function
• 🌟 dchen705: Remove unnecessary module import in browser/components/urlbar/tests/browser/head.js
• Ekerin Agboola: Remove old documentation related to the removed SEARCH_SUGGESTIONS_LATENCY_MS histogram
• ExplodingJoysticks:
  • Cleanup dead code in PageThumbs (preserveAspectRatio)
  • Dead code in services/crypto/modules/utils.sys.mjs#
• Gopalarathnam Venkatesan:
  • Remove unused lightweightThemes.getMoreURL pref
  • Remove orphaned selectHistoryMode JSDoc from browser/components/preferences/tests/privacy/head.js
  • 🌟 Fix incorrect ‘this’ in the Sync add-on install error handler
  • gBrowser.selectedTabs does not return tabs in tab order
• 🌟 Andrew: White flash on startup caused by abouthome_cache storing  incompatible startup frame
• 🌟 Kana: browser_privatebrowsing_resetPBM.js awaits an array instead of Promise.all, so the tab-close wait does nothing

Project Updates

Add-ons / Web Extensions

• As part of Nova about:addons work:
  • Restyled the Extensions panel empty states to match the Figma specs, including a new illustration for the disabled add-ons and private browsing states – Bug 2058450
  • Fixed a jiggle effect when scrolling through theme previews in about:addons – Bug 2059917
  • Added spacing between message bars and their sibling elements in the about:addons page (empty state promo, theme appearance mode control) – Bug 2066436
• Set focus on the extension permissions prompt dialog so keyboard users can reach it – Bug 2059855
• Removed activeAddons/activeTheme/activeGMPlugins from the legacy telemetry environment, now collected only through Glean – Bug 2055613

DevTools

• Nicolas Chevobbe [:nchevobbe] fixed an issue in the inspector to stop showing the HTML editor for nodes (e.g text or whitespace nodes) which should not be editable when F2 is pressed. (#2064213)
• Sebastian Zartner [:sebo] updated the documentation for the Rules view to include details around the  @media emulation panel added some weeks back. (#2063851)

• Chris Van Linden fixed an styling issue in debugger editor file search bar where the button hover background overlapped the focus outline (#2063466)
• Nicolas Chevobbe [:nchevobbe]  fixed an a11y issue where the keyboard focused sliders in the fonts panel did not have the correct contrast against the background. This allows keyboard users to easily see which control currently has focus. (#2062576)
• Hubert Boma Manilla (:bomsy) added telemetry to track the usage of styles sheets shown in the debugger (#2060500)

WebDriver

• Khalid AlHaddad improved Marionette and Remote Agent to quit Firefox with a custom error code when they failed to start their server.
• Khalid AlHaddad updated the moz:debugging module to properly handle nested pauses.
• Sameem updated the handling of user contexts to clean up the settings set per a user context (e.g., proxy settings or accepting of insecure certificates) also when a user context is removed outside of WebDriver BiDi.
• Henrik Skupin updated the WebDriver:GetElementTagName command to return the element’s qualified name.
• Henrik Skupin improved the Perform Actions command in both Marionette and WebDriver Bidi to dispatch intermediate events at more precise intervals when duration is greater than 0.
• Alexandra Borovova updated the “browsingContext.startScreencast” command to handle a screencast file creation on operating systems that don’t have a dedicated download folder.

Lint, Docs and Workflow

• The TypeScript linter has been promoted to tier-2.
  • There is no automation for the core type updates yet.
  • However, several areas have been working on support, hence the promotion to tier 2.
  • Until we get the automation in place, we will not be ready for wider roll-out, as it will be more likely that core patches will break the TypeScript reporting.

New Tab Page

• Developer experience improvement: it’s no longer necessary to create the WebPack bundles when updating New Tab JSX / SCSS files. This occurs automatically during the ./mach build [faster] step. Thanks to Nathan Barrett for his work there!
• Mike Kaply made it so that New Tab Settings honor Locked Preferences in policy by making the New Tab settings UI read and respect policy-locked preferences and disabling corresponding controls so managed/enterprise users cannot override locked prefs from the settings surface.
• Mike Conley landed a patch to address potential shutdown hangs / crashes when newtab trainhop XPIs are in the midst of being downloaded during a shutdown.
• Irene Ni made it so that we always show an add shortcut button for New Tab shortcuts when hovering the outside edge of the shortcuts area

• Irene Ni fixed some <hr> seperators that were leaking out of some containers by scoping the HR rules to the briefing-card container.
• Reem Hamoui added missing alt text/ARIA labels to the New Tab Page weather widget, restoring screen‑reader semantics for weather images in the NTP widgets.
• Jack Brown added scroll100 and scroll250 boolean metrics to the newtab ping to capture 100px/250px scroll‑depth thresholds for analytics—this is a telemetry/schema change with no UI impact.
• Scott Downe created the ‘spaces’ content layout variant for the New Tab Page, introducing an alternate DOM/CSS layout for Spaces that changes tile/content rendering and is gated by the Spaces rollout flag/pref.
• A Stocks widget is in-flight, starting with the US market

• • Nina Pypchenko [:nina-py] added a Markets/Watchlist dropdown to the Stocks widget on New Tab so users can switch views in-place; the dropdown selection is persisted in the widget state.
  • Nina Pypchenko [:nina-py] let users add default tickers to their Stocks Watchlist so new or reset users see a curated set of tickers and the add-flow now persists defaults to the watchlist storage.
  • Nina Pypchenko [:nina-py] added a small size to the Stocks New Tab widget, introducing a compact 1×1 Stocks tile in the Firefox New Tab Page layout so users on narrow windows or dense NTP configurations can keep Stocks visible without consuming medium/large slots.
  • Nina Pypchenko [:nina-py] updated the Stocks widget feed to fetch data for individual stock tickers, changing the widget network layer to per-ticker requests so added symbols get independent, timely updates and per-symbol errors are surfaced instead of breaking the entire feed.
  • Nina Pypchenko [:nina-py] added ticker search to find and add individual stocks, adding a search/lookup UI and add flow that calls the ticker lookup API and updates widget state/local storage so users can search, add, and immediately see new symbols on their New Tab Page.
  • Bryan Olsson added a plural selector to the Fluent string newtab-stocks-watchlist-full in the New Tab Page localization so the Stocks widget shows correct singular/plural wording for watchlist sizes across locales, fixing grammar that could confuse users when their watchlist count changes and touching the NTP stocks string bundle used by all localized builds.
• We’ve also started rolling out an experimental Privacy widget

• • Reem Hamoui changed the Privacy widget copy color to grey in the New Tab Page so the “Nightly blocks trackers as you browse. You will see them here.” text displays with correct muted contrast (2063205).
  • Reem Hamoui restored the ETP OFF state rendering in the New Tab Page privacy widget so the widget shows the actual ETP OFF status instead of misleading ‘blocks trackers’ copy for users who disable ETP (2063525).
  • Reem Hamoui applied UX fixes to the New Tab Page privacy widget to correct alignment, labels, and click-targets so users see and interact with the widget reliably and accessibility attributes behave as expected.
  • Reem Hamoui fixed the blocked-tracker count not updating after opening a new tab by ensuring the tally is recomputed on tab open (cache invalidation + UI binding refresh), restoring accurate tracker numbers in the widget.
• We’ve also started tinkering with some new layout variants
  • Here’s one such layout (widget column on left):

• • Irene Ni updated SectionsLayoutFeed’s 7-double-row-2-ad fallback to match Remote Settings so feed layout and ad fallback counts align with remote config, reducing layout mismatches and incorrect ad placements in feeds using the fallback (2063684).
  • Irene Ni implemented a carousel card type for the New Tab feed, adding slide-based card rendering and navigation hooks so users get swipeable/rotating cards in the carousel component.
  • Irene Ni deduped impressions for a carousel slide that cycles back into view, preventing duplicate impression pings when a slide reappears and improving the accuracy of telemetry/ad metrics.
• Dre cleaned up orphaned wallpapers in the wallpaper service to remove broken entries and reduce wasted storage so users no longer see missing background tiles.
• Dre uploaded new wallpaper assets to match updated margins so backgrounds render without cropping or misalignment under the new NTP layout.
• Nina Pypchenko [:nina-py] fixed wallpaper attribution rendering in the Nova New Tab flow by adjusting the Nova-specific NTP component’s conditional rendering (CSS/JS) so the attribution node is not skipped when the nova feature is enabled, restoring photographer/credit metadata on New Tab pages for users on Nova-enabled desktop builds and preventing missing attribution UX.
• We’re in early days in building out the infrastructure for a Recent Searches widget
  • Nina Pypchenko [:nina-py] added a blank widget scaffold to the New Tab Page widget registry for the Search team (bug 2065011), creating a no-op/placeholder widget registration hook so the Search team can iterate on experiments without changing current NTP visuals — no immediate visible impact for end-users until the widget is populated.
• Dão Gottwald fixed an unscoped panel-item::part(button) rule that stripped the icon slot from panel-items it didn’t own, restoring missing icons in New Tab panels and preventing blank/empty buttons in the UI.
• Maxx Crawford added support for auto-minimized the New Tab widgets section after a short delay, closing expanded widgets automatically to reduce visual clutter and accidental persistent open state.
• Irene Ni implemented the Topic Navigation Strip V1 in the New Tab Page, adding a horizontal topic-nav UI in the New Tab (top-sites/topics area) that improves discoverability and lets users switch topic feeds faster.

Picture-in-Picture

• Pier Angelo Vendrame made the document PiP video size spoofable under resist fingerprinting.
• Lukáš Lipinský fixed WebVTT tracks failing to display after opening a PiP window.

Search and Urlbar

Nova UI refresh

• Drew and Daisuke continued polishing the urlbar experience in Nova.
• Bug 2067360, Bug 2063170, Bug 2063167, Bug 2063127

Suggest

• Drew fixed alignment of the explanation text on various result types. Bug 2063460
• Drew enabled more providers (like Wikipedia) for DE, FR, IT regions. Bug 2064557
• Drew updated important dates suggestions for 2027 in DE, FR, GB, IT and US regions. Bug 2064437
• Dao fixed a regression with the result menu being empty on certain results. Bug 2066758

Adaptive autofill

• James is analyzing results of experiments and working with Product to let the feature ride to Release in the near future.

Quick actions

• Dale improved the Open Firefox Labs action. Bug 2063849
• Dale improved styling of disabled actions. Bug 2056488

Multi Context Address Bar

• Dao and Moritz made great progress with having the urlbar code work in different contexts, including across processes.
• Dao migrated some text input context menus (address bar, search bar, Thunderbird compose subject) onto a single shared menu with a new custom-item API, allowing removal of the legacy moz-input-box component.See EditContextMenu for documentation and usage. Bug 2064369.
• Dharma started refactoring the urlbar code to use extended classes. Bug 2064728
• New tab search bar has been enabled in Nightly! Bug 2062212
  • File a bug
• The uipc variant of urlbar tests is now tier1, failures will be backed out.

Other notable Address Bar fixes

• Dao made tabbing from the urlbar field focus the search field, if present on the toolbar, instead of the search button inside it. Bug 2009628
• Daisuke addressed an issue where an autofilled URL was ignored just after launching Firefox. Bug 2057763
• Moritz fixed a regression causing undo to no longer work in the urlbar. Bug 2061633
• Moritz fixed a regression with the placeholder text in the urlbar showing garbled characters. Bug 2063779

Search

• Mark added support for POST search engines to the contextual actions in the urlbar. Bug 2064047
• Caleb fixed an accessibility issue in the add search engine dialog. Bug 2041438

Places

• Caleb fixed a bug where moving a group of folders could move some bookmarks out of their parent folder. Bug 2044707

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

• 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!

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

• 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