I’ve just released new version of Firefox Tweaker 2.9 that can enable preview of Mozilla’s new Proton Interface. Proton is Mozilla’s redesigned interface for Firefox which is planned to be released to all users with Firefox 89. You can try it out now in Firefox 88. While some things are a bit weird, some are surprisingly better. Like the god awful oversized twitching URL bar which feels much better under Proton. Give it a try if you want.
The tweak controls several parameters at once. Parameters are listed under Help button of Proton interface and you can individually adjust them under about:config if you desire to do so. I’ve decided to pack them all under single checkbox for convenience purposes.
Micro page for more details: