Every few Firefox releases there's one where they helpfully throw new junk in your face or mess with your settings. Firefox 118 is both.

Mozilla has added a translation engine that they say is client-side, based on an engine called Bergamot that they created. They removed all languages other than the one I'm writing in from my settings, even though I read (poorly, and for sport) in other languages. And then they put a pop-up over every page that's not in English - including some I've deliberately switched to other languages - offering to translate it.

Getting rid of this requires an about:config hack that I saw only on The Site We've Chosen Not to Use. So here's the incantation:

browser.translations.automaticallyPopup false

and if you're really angry

browser.translations.enable false

And put back any languages it removed from your site preferences.

Honestly, if I didn't know these people weren't Google, I'd be really suspicious. But with Chrome's stellar Ad Privacy, I have to put up with Mozilla's crap, as the clock has to be ticking even for the 'good guy' Chromium derivatives.