I know that feeling of panic!
Good job you had the Extension List Dumper report!
Don't worry, you didn't cause any problems for others - well, not for me, at any rate.
I knew to be cautious with an unknown source for MrTech. It's probably a ß version - a work in progress.
For future reference: If you bring up FF with SHIFT-Click on the shortcut, then I think it should load with NO add-ons running, and you can then make changes from there. I had to do that with a couple of add-ons before when I was updating FF. Maybe one of them was the older version of MrTech, I'm not sure.