Genuinely asking : Who is behind librewolf and why should i trust them? They don't seem to be available in any official repos yet other than ones they self-published
They also have links to join other community spaces so you can probably ask them yourself.
> They don't seem to be available in any official repos yet other than ones they self-published
The only official repos are the ones which the community decides are so. https://codeberg.org/librewolf They've been around long enough that if they're not on github (for example), it's probably intentional. (One can imagine why this particular community might prefer to avoid directing people to Microsoft-owned github.)
I'm not sure what you think of as "official", but it's been in nixpkgs for years at least. You can also take a look at what it's doing. The librewolf repo itself is basically a collection of generally small patches. Mostly you've got patches to change branding and remove antifeatures, plus fixes like preventing pages from detecting you've opened devtools and enabling JXL support.
https://librewolf.net/