Breaking (shitty and user-hostile) websites by default is still a lot better than ignoring your privacy preferences and trying to psychologically manipulate you by default.
privacy.resistFingerprinting is something I had to set to false in my user.js, but I had my own user.js with my own privacy settings anyway. The rest of the settings it provides are very good for a default though.
I'm guessing that was because Debian refused/wasn't able to sue the Firefox branding and they extended that to the user agent. So a ton of sites just saw Iceweasel as the UA and broke because it was unexpected.
LibreWolf isn't strictly a fork of Firefox, it's a preconfigured installation that locks things down and disables anti-features. So it's strictly accurate to use the Firefox user agent, because that's what actually gets compiled.
Wasn't the issue with the Iceweasel UA purely on Debian's end, them not like or agreeing to the Firefox terms? I don't think most forks would have that issue
Can you provide any evidence that the User Agent name was a trademark issue. As in the name exposed to websites. Because that is the only thing that matters here and also where everyone claims to be a variant of Mozilla for compatibility.