It works, but it's buggy. The extension name does not appear in the settings and context menu. It looks like a (oddly) translation error. I suggested corrections on Github, I hope the developer sees it.

I'm not much techy but I think that this addon is great for Google Translate users. Still it is impossible for a user to choose the account in which they want to translate the text. You would just need to ask the user to modify (as an optional thing) the link of Google Translate. With this feature I could actually choose the account I usually use to translate things!! (We would just need to add a "/u/1/" and it would search on the second Google Account in the list)

ojôioi

The extension is great, and has always worked perfectly. Unfortunately it hasn't been running for a few weeks: the application starts up, but then remains an empty modal continuously loading.
I abandoned it to move on to something else. I hope the problems will be resolved soon (some info for the developer: I have Firefox 84.0.2).