Categories: News

Inspector Performance and Other Improvements – These Weeks in Firefox: Issue 155


  • Alex added added a new option to log frame return to the nascent JS Tracer feature (bug)
    • This can be really useful paired with the “Log function arguments and returned values”. See the example below, tracing a Redux reducer on about:home
    • The JS Tracer is a tool that the DevTools team is developing to log JavaScript execution at runtime. This can be very helpful when debugging or exploring a new JavaScript codebase!
      • Set devtools.debugger.features.javascript-tracing to true to enable the JS Tracer feature and try it out!
  • Nicolas fixed a performance issue in the Inspector when showing a lot of rules (bug)
    • for 5000 rules, on Nicolas’s engineering machine, this went from 7 seconds to 50 milliseconds!
  • Marco enabled cross-container tab searching in Nightly (1876743). Users can now search in the URL bar for tabs open in different containers. This behaviour can be controlled through the browser.urlbar.switchTabs.searchAllContainers boolean pref.
  • The Firefox View team has added new tab indicators to the Open Tabs section (sound playing, notifications, etc) and the option of sorting Open Tabs by recency. Both are slated to ship in Firefox 124!

Friends of the Firefox team

Resolved bugs (excluding employees)

Script to find new contributors from bug list

New contributors (🌟 = first patch)

Project Updates

Developer Tools

  • Redfire fixed an erroneous comment in Console.cpp (bug)
  • Arai migrated ESMified devtools/client/performance-new JSMs (bug)
  • Dylan made the Netmonitor to show resources loaded from a file url (bug)
  • Nicolas added an option in the settings panel to control the behavior of the Enter key in the Rules view (bug)
  • Nicolas started the migration of DevTools to CodeMirror6. The first consumer is the EventTooltip, in the markup view (bug)
  • Hubert will manage the migration of the Debugger to the new CodeMirror version, which will happen incrementally behind a pref, until everything is ready (bug)
WebDrive BiDi
  • Thanks to Jing Zhu for updating various deserialization methods in RemoteAgent to match the specifications more closely (bug).
  • Kagami updated Marionette permissions to handle storage-related permissions (bug).
  • Sasha implemented the storage.getCookie command, which allows to retrieve cookies (with support for partitions and filtering) (bug).
  • Sasha also implemented the storage.setCookie command to create new cookies (bug).
  • Julian added basic support for two network interception commands network.continueRequest and network.continueResponse (bug). We also removed the experimental flag gating the various network interception commands (bug).
  • Julian implemented the userContext parameter for browsingContext.create, which allows to set user context (Firefox container) owning a new tab or window (bug). We added the userContext field to events and payloads describing a browsing context, so that you can check which container owns a given browsing context (bug).
  • Julian fixed a bug for the network.fetchError event which was missing in case a network request failed really early on (bug).
  • Henrik fixed a bug with Get Element Text (WebDriver classic) which could fail when used with web components (bug).

ESMification status

    • ESMified status:
      • browser: 100%!
      • toolkit: 99.83%
      • devtools: 89.09%
      • dom: 96%
      • services: 98.94%
      • Only 10 JSMs left in the tree!
      • Total:  99.34% (+.86% from last week)
  • #esmification on Matrix

Information Management

  • Firefox View
    • More Open Tabs features we’re planning to ship in 125: Pinned Tabs, Bookmark and New Tab pinned Indicators
  • Session Restore


  • bradwerth has posted a patch that makes the Picture-in-Picture player window use the native macOS fullscreen mode


Reader Mode

  • Irene landed a patch that fixes Reader Mode losing its scroll position when navigating a link and returning back (1780350)
  • Irene also implemented an enhancement allowing for Reader Mode paragraph spacing to adjust alongside line-height (1874983)

Screenshots (set screenshots.browser.component.enabled to true)

Search and Navigation

Enhanced Cross-Platform Suggest
  • Drew updated the MDN suggestion code, weather suggestion code and quick suggest config to account for all three of those suggestion types being implemented in Rust (1877595, 1878441, 1878444)
  • Drew finalized the UX for Yelp suggestions (1878727)
  • Drew added a “Local recommendations” group label for Yelp suggestions (1879397)
  • Drew updated the Yelp desktop suggestions to accommodate certain prefix-matching rules that are applied to what the user types into the urlbar (1879642)
  • Daisuke implemented the result menu for Yelp suggestions (1878728, 1879637)
  • Daisuke ensured Yelp suggestions are labeled as “sponsored” (1878814)
  • Daisuke added a Nimbus variable for testing Yelp suggestions as a top pick (1877920)
  • Daisuke allowed Yelp suggestions to pull location information from the Merino service if that Yelp suggestion didn’t already have a location (1878206)


Search and SERP (Search Engine Result Page) telemetry
  • James and Stephanie have continued their work on the SERP categorization project (1848197, 1879737)
  • James fixed two issues with how we record SERP telemetry when the SERP is a single page app (1878062, 1879404)


Consolidated Search Configuration
  • Mandy fixed an issue where prior search settings were lost when using Amazon as the default search engine in Spain (1878277)


General Search Service
  • Standard8 simplified the way the search service loads engines (1879126)


General Improvements

Karandeep landed the first in a series of patches to remove an ultimately unused API for urlbar experiments (1855958)

No comments yet

Post a comment

Leave a Reply

Your email address will not be published. Required fields are marked *