THANKS IN ADVANCE FOR READING THIS. Am newly signed onto Android Mobile FireFox.

I agreed to the Extension "Downloading YouTube". Then, an ominous warning popped-up. Now I regret having pressed the "download" consent. Recently, my YouTube Premium Account was hacked. There were stranfe noises & unnerving screeches, preceeding YouTube freezing. Eventually, I decided to Factory Reset the phone. Discovered that my YouTube History had movies/videos that I never watched. This is why I thot it wise to have YouTube protection. However, how would I know if the Extension download occurred? I don't see any addition to my App Library.》》 Maybe my Android Securuty blocked it. How can I check this? I'm not computer intelligent. Don't know the difference between a Mobile Phone App or a Mobile Phone Extension. Very much appreciate your help. Thank You!!