My cringe with Firefox are misfeatures like window.onbeforeunload. They deliberately break the expected behavior due to an unreasonable decision, but no browser is perfect.
They tried a fix and it broke YouTube. So it seems like a reasonable fear. https://bugzilla.mozilla.org/show_bug.cgi?id=349259#c54
> The patch ... is literally to remove "!important" from one CSS file
It isn't a simple one line fix, as Firefox developer kindly explained. https://bugzilla.mozilla.org/show_bug.cgi?id=349259#c76
>That patch would not be welcome.
They describe what work would be required (and where the changes would likely be) for the patch to be accepted in the bug. https://bugzilla.mozilla.org/show_bug.cgi?id=349259#c80
Problem is, not everybody knows C++. Having a bug open for 7 years makes me think the issue will never be resolved. All I can do is wait or use another browser. One annoyance I have with Firefox is the lack of built in keychain support. This really summarizes how I feel: https://bugzilla.mozilla.org/show_bug.cgi?id=106400#c94
As for the original bug, this post: https://bugzilla.mozilla.org/show_bug.cgi?id=349259#c82 seems to suggest every browser but Firefox supports changing line-height. Wouldn't Firefox be going against the expected behavior?