Great and simply a must have, especially since Mozilla crapped FF last version (107) "update" with a bug for tooltips messages now partially merging under other objects.
It would be great if the rest of thumbnail's description (channel name, upload date, etc.) have been affected the same way.
Thank you, now I can at least read video's title.

So ! useful add-on. Damn I've been annoyed by those truncated titles for so long, I'm glad I finally looked for a solution. And the first one I try works perfectly :)
Thanks a lot for coding and sharing that.