Luckily, there’s a solution…
I've been toying with the idea of setting up a build enviroment for LibreWolf myself but that would still require auditing the patches and their changes as they come in every day.
Somehow I'd trust a group of randos more than most corporations
But a browser is none of these. If one of the devs gets their machine hacked, a trojanized build can reach you in mere seconds if you are unlucky enough to start your browser shortly after the build pipeline gets infected.
further reading, for anyone looking for an alt browser/config: arkenfox (af) v librewolf (lw) v mullvad browser (mb) from the af owner, mb maintainer, and lw, ff, & tor contributor: https://github.com/mullvad/mullvad-browser/issues/1#issuecom...