Hi Hebrews12_29, do you mean you are using the TOR Browser? The TOR browser uses technology from Mozilla, but the program files should be in a distinct program folder and not cross over.

I don't know whether the TOR Browser will re-use any data/settings from an existing Firefox profile. I think it would be worth asking TOR support. Or you could try creating a new profile to get a clean start. Here's how:

New Profile Setup

Inside your Firefox-based browser, type or paste about:profiles in the address bar and press Return to load it.

Click the Create a New Profile button, then click Next. Assign a name like April2019, ignore the option to relocate the profile folder, and click the Finish button.

After creating the profile, scroll down to it and click the Set as default profile button below that profile, then scroll back up and click the Restart normally button. (There are some other buttons, but please ignore them.)

Firefox should exit and then start up using the new profile, which will just look brand new. Please ignore any tabs enticing you to connect to a Sync account if you don't want those old settings in this profile.

Does this look more like what you were expecting??

To switch back, open the about:profiles page again, click the Set as default profile button for your normal profile, then click the Restart normally button to get back to it.

Thank you for your assistance. That was clean solution as far as I can tell and worked immediately. Is there a way to uninstall any _invisible_ Firefox files, and if so how do I proceed?

If you were running Windows, I would have some suggestions, but I don't know where to check on Mac. Maybe this article will help: Profiles - Where Firefox stores your bookmarks, passwords and other user data.