Click the icon that's shaped like a jigsaw-puzzle piece at the top right of the screen. Next click the gear-wheel next to the extension you want to remove then click "Remove Extension."

I specifically want to remove search.funsafetabsearch.com It isn't on the list and appeared from nowhere today blocking me from google

You can check for recently installed suspicious or unknown extensions. See:

• https://support.mozilla.org/en-US/kb/disable-or-remove-add-ons

You can do a malware scan, just to be sure.

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware