Giving You More Control - These Weeks in Firefox: Issue 204
Katherine Patenio
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
alt text: Firefox context menu video controls like Pause, Unmute, Speed and Loop.
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)
alt text: Tooltip in Firefox DevTools for mismatched syntax with attr()
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
🌟 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
Address Bar
Nova UI refresh
Drew and Daisuke continued working on reorganizing styles and updating the urlbar for Nova.
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.
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.
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.
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.
Other
Marco, Drew and Daisuke fixed several intermittent test failures.
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.
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".
Below the fold
General triage
[mconley] TIL Element.checkVisibility exists and is very handy!
[jdescottes] Firefox DevTools MCP exists!
MCP (Model Context Protocol) that lets AI assistants drive Firefox via WebDriver Classic and BiDi
Already configured by default in your firefox clone via .mcp.json
Basic browser automation tools: open tab, navigate, screenshots, script execution
Can be configured to have Chrome JS access, use MOZ_LOG, set preferences
Can use a stock Firefox or your local build. Android support in the next release
Links: github repository https://github.com/mozilla/firefox-devtools-mcp, npm package: https://www.npmjs.com/package/@mozilla/firefox-devtools-mcp
Additional docs at https://firefox-source-docs.mozilla.org/ai-agent-tools/firefox-devtools-mcp.html
On matrix and slack: #firefox-devtools-mcp . Bug tracking is on bugzilla.
[mconley / florian] Better tooling to diagnose intermittent test failures
Also note that we’re really just synthesising and humanising the stuff that's on the Wiki, which is freely available from here: https://wiki.mozilla.org/Firefox/Meeting, so check that out if you want the source material. It'll also be posted (minus the Below the Fold stuff) to the Nightly blog.
Finally, if there's a Firefox-ish team that you feel isn't being represented here, please let them know about the above meeting so we can get their updates.
Keep on rockin' the free web,