ISSUE A FIREFOX ADD-ON THAT WORKS WITH VERSIONS 56.0 AND EARLIER (I.E., THOSE VERSION THAT DON'T USE WEB EXTENSIONS.) MILLIONS OF PEOPLE DID NOT UPGRADE (OR IS THAT DOWNGRADE) TO THE VERSIONS OF FIREFOX THAT IMITATE CHROME !!!! YOUR CURRENT ADD-ON IS A WEB-EXTENSION-ONLY ADD-ON.