- At first, the discussion on bugzilla [1] is reasonable: user stylesheets off by default for performance, and there's even backward compat code enabling the pref during Firefox 68 if you are using them. All good...
- ... but then comes this legacy in the pref name :-| :-| :-|
I hope Mozilla keeps the feature alive, it's appreciated by many "power" users.
EDIT good news: re-reading recent comments, in https://bugzilla.mozilla.org/show_bug.cgi?id=1541233#c61 , Florian Quèze (mozilla dev) affirms: "the word 'legacy' was used in the preference name to avoid giving the impression that with this new preference we are adding a new customization feature. I'm not aware of any plan to drop support for these files".
Ugh, if you're gonna pull this shit make sidebar tabs first class! They knew this way before they switched, gave some lip service to make sure the most popular extensions would get the support they needed, and now however many releases later i still have to dig through hidden files and hash-named profile directories to make this work right. And still no usable alternative to tab groups last time I checked, which they took out of core with the reasoning that it should be an extension. At least adblock still works.
userChrome.css to the rescue:
- Tree Style Tab's wiki offers tips to do exactly that: https://github.com/piroor/treestyletab/wiki/Code-snippets-fo... .
- Or you can combine the address and tab bar: https://github.com/rstacruz/firefox-stealthfox
If none is to your exact taste, https://www.reddit.com/r/FirefoxCSS/ may help.