Review Mozilla 1968037: [meta] Settings Redesign Conversions 2025

🔍 Bugzilla Audit

Bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1968037

Description

New upstream settings redesign. We should:

  1. Review the full set of changes.
  2. Make sure the Firefox settings we want to hide are still hidden.
  3. Convert our additions to the existing firefox categories, like "letterboxing" or "onion authentication", integrate well with upstream's changes. Similarly for any settings we modify, like the contrast settings.
  4. Convert our Tor Browser "Connection" settings.

These should probably be split into smaller tasks.

/cc @donuts @felicia