149 rebase, part 1 (#44702)

Merge Info

Issues

Resolves

• #44702

Merging

Target Branches

• tor-browser - !fixups to tor-browser-specific commits, new features, security backports
• base-browser and mullvad-browser - !fixups to base-browser-specific commits, new features to be shared with mullvad-browser, and security backports
  • ⚠️ IMPORTANT: Please list the base-browser-specific commits which need to be cherry-picked to the base-browser and mullvad-browser branches here

Target Channels

• Alpha: rapid release, 16.0
• Stable: esr140-15.0
• Legacy: esr115-13.5

Issue Tracking

• Link resolved issues with appropriate Release Prep issue for changelog generation

Review

Request Reviewer

• Request review from an applications developer depending on modified system:
  • NOTE: if the MR modifies multiple areas, please /request_review all the relevant reviewers
  • accessibility : henry
  • android : clairehurst, dan
  • build system : boklm
  • ci/cd: brizental, henry
  • extensions : ma1
  • firefox internals (XUL/JS/XPCOM) : jwilde, ma1
  • fonts : pierov
  • frontend (implementation) : henry
  • frontend (review) : donuts, morgan
  • localization : henry, pierov
  • macOS : clairehurst, dan
  • nightly builds : boklm
  • rebases/release-prep : brizental, clairehurst, dan, ma1, pierov, morgan
  • security : jwilde, ma1
  • signing : boklm, morgan
  • updater : pierov
  • windows : jwilde, morgan
  • misc/other : pierov, morgan

Change Description

• Cherry picking commits FIREFOX_NIGHTLY_148_END..tor-browser-148.0a1-16.0-2-build1: https://gitlab.torproject.org/boklm/tor-browser/-/commits/rebase-149
• Cherry picking commits tor-browser-148.0a1-16.0-2-build1..tor-browser-148.0a1-16.0-2.

I will open separate comments for each notable conflicts.

How Tested

Ran linters.

I did not try Desktop and Android builds yet (I will remove draft status after doing that).