Had 64 open tabs and it only converted 4 of them :(

Absolutely useless. After restoring tabs Firefox tried to load content of all tabs at once which resulted in an infinite loop of loading without any result. Had to kill FF with the Task Manager. Lost all tabs. Avoid.

Je ne trouve pas comment régler l'extension sur firefox (en cliquant droit sur le logo de l'extension) alors que c'est possible sur chrome. Arrangez ça svp.
Sinon pour régler les options il suffit de cliquer sur le bouton de l'extension et une page s'ouvrira...

I tried this add-on today, having so far been fairly pleased with it on FF for Windows. I had 30 tabs open on FF for Android. OneTab saved the most recent three and deleted the other 27 from existence. The fail is impossible to exaggerate. I will probably remove this and hunt for alternatives on FF for Windows too.

Used to have this on Chrome in 2018, worked. That's why I trusted it and didn't export.
Now, in 2020 on Firefox/MacOS, didn't restore 48 tabs, but removed them from the list. Hours of work destroyed, no chance to know which 48 of ~ 1000 tabs were relevant to me.