Both are good. Librewolf is more like vanilla Firefox, just configured way better by default. Mullvad Browser is like a port of the Tor Browser (also based on Firefox) for the clear web (or for use with Mullvad’s VPN, or whatever). Also configured very well by default. Mullvad Browser has better anti fingerprinting stuff built-in but as a result of its unusual configuration some sites might be broken. Librewolf is kind of the opposite in that regard - sites won’t be broken but you’ll be easier to fingerprint. In any case, they both are at the top of the best Firefox variants I’d say.
I like LibreWolf, but I don’t like that it wipes cookies and session tokens each time you launch it. I understand why they do it, but it’s a consideration outside my threat model, so it just annoys me.
You can also easily set specific sites’ cookies not to be wiped, I use this to have websites I trust to store my data for convenience, but any random tracker-infested blog to forget me as soon as the browser closes!
And also, Mullvad Browser does this by default, as well. I think theirs can’t even be configured on a per-site basis.
Wait. Mull browser is mullvad browser?
No, mull is a fork of Firefox meant for android and developed by the divestOS team, while mullvad is a completely different fork, only for desktop atm and developed by mullvad (the VPN company)
they both focus on privacy and integrate Tor patches and modify some configs to better resist fingerprinting, but mullvad browser goes a step further with the tor integration, going as far as storing all data in RAM, so it deletes every cookie, history etc on restart. Could be an advantage, could be a disadvantage, up to you
Firefox + Arkenfox … :P Using Mullvad as a backup before having to use chromium for any dirty stuff. Librewolf seems to be like a good recommendation for non-technical people. Although I am not sure which browser has less breakage Mullvad or Libre.
Honestly at this point, normal firefox with ublock and custom user agent switched to chrome.
The thing is youre telking websites you are using chrome so theyll look at their stats and say "everybody ises chrome, lets just design for chrome "