Noté 5 sur 5 étoiles

par Utilisateur ou utilisatrice afa19a de Firefox le déc. 5, 2017 · lien permanent

Due to changes in the Firefox API, this add-on cannot be made compatible anymore for Firefox 57 and above. Best alternative is to reinstall Firefox 56 and to disable automatic updates.

https://www.wikihow.com/Downgrade-Firefox