These Weeks in Firefox: Issue 102

Highlights

• As part of Fission-related changes, browser.tabs.delectLanguage has been migrated away from MessageChannel.jsm and to use the JSWindowActor messaging instead, which has also nicely reduced AWSY’s Base Content JS memory usage 3%-4% across all desktop platforms \o/
• We’re starting to get numbers back on how the Fluent migrations have been impacting startup:
  • There appears to be evidence that the localization cycle for the first window is ~32% faster for the 95th percentile of users on Nightly, and ~12% faster for the 75th percentile.
  • Subsequent new windows see localization cycle improvements of ~12% for the 95th percentile
  • TL;DR: Removing DTDs from the main windows has improved startup time and new window opening for some of the slowest machines in our user pool.

Friends of the Firefox team
Fixed more than one bug

• Itiel

Project Updates

Add-ons / Web Extensions

Addon Manager & about:addons

• Fixed a bug related to the addon descriptions not being localized as expected when switching the browser to a different locale – Bug 1712024
• Introduced a new “extensions.logging.productaddons.level” about:config pref to control log level related to GMP updates independently from the general AddonManager/XPIProvider logging level – Bug 1733670  

WebExtensions Framework

• As part of Fission-related changes, browser.tabs.delectLanguage has been migrated away from MessageChannel.jsm and to use the JSWindowActor messaging instead, which has also nicely reduced AWSY’s Base Content JS memory usage 3%-4% across all desktop platforms \o/

WebExtension APIs

• Starting from Firefox 94, a new partitionKey property is being introduced in the cookies API, this new property is meant to help extensions to better handle cookies partitioned by the dFPI feature
  • The new partitionKey will be documented in the cookies API reference pages on MDN (mdn/content pull request: https://github.com/mdn/content/pull/9382)

Downloads Panel

• Many tests being addressed and fixed with improvements pref enabled (ticket)
• [kpatenio] New context menu item being worked on for new pref (ticket)

Fission

• The Fission experiment on Release has concluded, and the data science team is now analyzing the data. So far, nothing has jumped out to us showing stability or performance issues.
• Barring any serious issues in the data analysis, the plan is to slowly rollout Fission to more release channel users in subsequent releases.

Fluent

• M2 increased by 5% and M3 by 1%
• kpatenio ported some more .properties strings to Fluent!
• niklas converted places.dtd to Fluent, and removed the rest of browser.dtd!
• [kpatenio] will be working on some migrations related to Forms and Autofill

Password Manager 

• A couple recent highlights:
• Riding the trains: Bug 1732901 – Enable multi-page login form in beta and release – this is where the username field is on one page and the password on another. 
• Bug 1713133 – The meatball menu from about:logins is improperly displayed when Increase contrast is enabled

Performance

• dthayer landed a fix that improves scaling of iframes with Fission enabled
• mconley helped harry find a solution for a white flash that can occur when a theme is applied to about:home during the first boot
• Special shout-out to zombie from the WebExtensions team for helping to reduce Base Content JS memory usage by 3-4% on all desktop platforms!
• We’re starting to get numbers back on how the Fluent migrations have been impacting startup:
  • There appears to be evidence that the localization cycle for the first window is ~32% faster for the 95th percentile of users on Nightly, and ~12% faster for the 75th percentile.
  • Subsequent new windows see localization cycle improvements of ~12% for the 95th percentile
  • TL;DR: Removing DTDs from the main windows has improved startup time and new window opening for some of the slowest machines in our user pool.

Performance Tools

• Isolated web content processes now display eTLD+1 of their origin in the Firefox Profiler timeline when Fission is enabled.

Before

After

• Gecko profiler Rust marker API has landed. It’s possible to add a profiler marker from the Rust to annotate a part of the code now. See the gecko-profiler crate for more information. Documentation is also coming soon.

Search and Navigation

• Daisuke has replaced the DDG icon with one having better quality. Bug 1731538 
• Thanks to Antonin Loubiere for contributing a patch to make ESC actually undo changes in the separate search bar, instead of doing nothing, more similarly to how the address bar behaves. Bug 350079 

Screenshots

• Thanks again to module owner Emma whose last day was Friday. Sam Foster will take over as module owner. 
• niklas working on bug 1714234 that fixes screenshot test issues when copying image to clipboard.