Categories: News

These Weeks in Firefox: Issue 68


  • The “Omniscient” Browser Toolbox will be enabled by default in the coming days
    • This is a browser developer toolbox with the ability inspect/debug multiple processes
    • As a follow up, the Browser Content Toolbox (which debugs the content process of for the current tab) will be no longer needed and removed.
  • The JavaScript Debugger’s new Watchpoints feature, which let you pause on object property get/set, are on by default in Nightly and will ride to DevEdition for more QA and user feedback
    • The JavaScript debugger is paused at a line of code where a property was set, due to a watchpoint on that property.

      A watchpoint paused on this.model.attributes.completed being set.

  • The Network Monitor’s new Request Blocking lets you block requests based on matches patterns – it is now enabled by default on Nightly and DevEdition
  • User-Initiated Picture-in-Picture for videos is now enabled by default on macOS and Linux on Nightly! Please test it out, and file bugs against this meta for us to triage.

Friends of the Firefox team

Resolved bugs (excluding employees)

Fixed more than one bug
  • Alex Vincent [:WeirdAl]
  • Ben Campbell
  • Christoph Walcher
  • Chujun Lu
  • Florens Verschelde :fvsch
  • Itiel
  • jaril
  • Mustafa
  • Tim Nguyen :ntim
New contributors (🌟 = first patch)

Project Updates


Add-ons / Web Extensions

  • Shane landed the first bits of the changes to the webextensions CSP (Bug 1581611, Bug 1587939, Bug 1581609, content script CSP is currently behind the extensions.content_script_csp.enabled and extensions.content_script_csp.report_only prefs), and fixed a bug related to the behavior of the “private browsing” checkbox included in the post install notification (Bug 1581852).
  • Tomislav fixed AddonManagerWebAPI::IsAPIEnabled in Fission out-of-process iframes (Bug 1591736)
  • Mark Striemer moved the about:addons page header, page options, search addons field and global warnings from XUL to HTML (Bug 1545346)
  • Andrea Marchesini is moving secure-proxy experimental APIs into mozilla-central (Bug 1592687, Bug 1592932), and added the third-party state to the request details provided by the webRequest and proxy API events (Bug 1591900)
  • Gijs made sure that Firefox reuses an existing about:preferences tab when the user is opening it from the about:addons page (Bug 1592600)
  • Matt Woodrow fixed webRequest API regression (Bug 1590898, recently regressed by Bug 1583700)
  • Graham extended the browserAction/pageAction onClicked API event to allow extensions to receive “middle-button” mouse clicks and extended the onClicked event details to also include mouse buttons and keyboard modifiers states (Bug 1405031). Thanks Graham for contributing this enhancement!
  • Itiel fixed the alignment of the warnings/errors messages part of the about:addons extensions shortcuts view when the RTL mode is enabled (Bug 1575472). Thanks Itiel for contributing this fix!
  • Trishul fixed a webRequest bug triggered by webRequest API events received for tabs that are already closed (Bug 1447807). Thanks Trishul for looking into it and contributing a fix!

Developer Tools

  • Console’s multi-line editor mode now has shortcuts for importing and saving your snippets back files: Ctrl/Cmd-O and Ctrl/Cmd-S . This is based on feedback from users who were used to these shortcuts when using Scratchpad.
  • Contributor Sorin Davidoi optimized the Debugger to use less resources when the tab is in the background.
  • Browser Toolbox’s –jsdebugger for can now be overridden with another Firefox executable that will be used for the Browser Toolbox, so you can run DevTools in an optimized build: ./mach run –jsdebugger $NIGHTLY


  • M4 came and went with 130 or so tests still not enabled. Teams will continue to fix tests while making the Fission enabled browser stable enough for daily use, which is our M5 target.
  • Classified front end work for M5
  • Some work already finished:

New Tab Page

  • Getting Discovery Stream working for the de locale. (right now it’s just en-US and en-CA)
  • Turning personalization back on for sponsored content.
  • Some minor UI and UX fixes and some experiments.

Password Manager


Performance Tools

  • The profile metadata panel now shows the settings that were used to capture the profile.
    • The Profiler metadata panel is showing what settings the profile was gathered with. It lists the sampling interval (1ms), the buffer capacity (16.0MB), the buffer duration (Unlimited), and the profiler features that were enabled.

      This helps us see at a glance how a profile was gathered, which can help explain some of the patterns within the profile.

  • There’s a new Track IPC feature (off by default) that can be enabled from the profiler’s capture panel to track async IPC.
    • The Profiler showing the Marker Chart, and indicating when IPC messages were sent and received.

      The parent process appears to be sending quite a few IPC messages here.

    • Example profile of the IPC happening when opening new tabs.


Search and Navigation

Address Bar
  • Regression fixes:
  • Visual redesign (aka “megabar”, Firefox 73)
    • Temporarily disabled in Nightly, we are working on a new revision of the design, additional feedback on the old revision was not useful. Will re-enable once we are closer to MVP.
    • New one-off buttons flex behavior for small windows
    • Removed some more legacy urlbar code, especially from autocomplete
  • Search Interventions experiment (Firefox 72)
    • Experimental add-on is being worked on.
  • Search Nudges experiment (Firefox 72)
    • Project revised to use the Search Interventions API.

User Journey

  • Launched a couple of “Relationship” CFRs in nightly and beta, riding the trains to release
  • What’s New feature made it to the release channel
  • Investigating user-agent attribution focusing on “Chrome switchers” to show contextual onboarding, e.g., dynamic first-run cards
  • Potentially expanding new-user onboarding cards to show for pre-Skyline profiles with remote messages to current release users

3 comments on “These Weeks in Firefox: Issue 68”

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  1. Alex Vincent wrote on

    Thanks for the shout-out. I don’t get to write code for Mozilla very often these last few years.


  2. Olivier wrote on

    New versions of Firefox 72.0a1 are not opening anymore on my Mac Mini running 10.9.5


  3. Olivier wrote on

    Firefox nightly is working fine again on my Mac Mini running 10.9.5


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