Essential Noté 5 sur 5 étoiles
This is the first thing i install on any copy of Firefox i use. So many features it's almost overwhelming, but take the time to adjust to your liking, export the settings and import it everywhere. If i were told i could only have one add-on, this would almost certainly be it.
The only thing it seems to be missing is a tab preview, but there's other singular extensions that do that (like Tab Scope) so no great loss.
If you're an Opera convert - you NEED this extension.
I can only say thank you and donate (done).