"Automated translation of web content is now available to Firefox users! Unlike cloud-based alternatives, translation is done locally in Firefox, so that the text being translated does not leave your machine."

I got to see the early demos of this and it is jaws-on-the-floor bonkers wizard magic. Entirely local - and good - translation with no cloud service and like 6MB of storage per language.

https://www.mozilla.org/en-US/firefox/118.0/releasenotes/