Firefox 89 - reverting UI changes

Firefox 89 looks degenerately (code name “Proton”). Some findings for reversing:

user_pref(«browser.proton.enabled», false);
user_pref(«browser.proton.contextmenus.enabled», false);
user_pref(«browser.proton.appmenu.enabled», false);
user_pref(«browser.newtabpage.activity-stream.newNewtabExperience.enabled», false);
user_pref(«browser.proton.tabs.enabled», false);
user_pref(«browser.proton.doorhangers.enabled», false);
user_pref(«browser.proton.infobars.enabled», false);
user_pref(«browser.proton.places-tooltip.enabled», false);
user_pref(«browser.proton.urlbar.enabled», false);
user_pref(«», false);

Or use about:config to change preferences.
I cannot find some settings, maybe they are only for Windows?

Mine FF starts to use dark theme after update. How to change it to previous light theme?

Restoring search with a search field in a new tab:
browser.newtabpage.activity-stream.improvesearch.handoffToAwesomebar set to false.

Setting “browser.proton.enabled” to false is only going to work as a temporary measure, it will be removed on a future release. :wink:

See here :

for an alternative using userChrome.css

Looks like that pref will be removed during the Firefox 90 cycle.

See comment #6 by “:Gijs (he/him)” in this bug report: