Best tool. I am the guy who made the post on r/firefox Subreddit mentioning your add-on. It has over 350 upvotes now means people truly find your work amazing. However, a dude came in and posted that he reported your add-on for violating Firefox's policy. He wrote:
"It's good that you found another fugitive! I will immediately send a request to Mozilla to remove it for violating the policy: Add-ons must be self-contained and not load remote code for execution.
The fact is that Firefox prohibits any inline translator like Chrome. You can read about it here: https://www.jeremiahlee.com/posts/page-translator-is-dead/
And here: https://bugzilla.mozilla.org/show_bug.cgi?id=1589974"
This is his reddit profile: https://old.reddit.com/user/patrocl
From his comments so far, I guess he had made a similar add-on in the past which got removed from add-on store for supposedly violating some weird Firefox rule.. I think your add-on is in danger now. :(