(not sure if this would also leave you susceptible to actual malicious addons) If you want the extension without flipping the about:config entry. You can open

(not sure if this would also leave you susceptible to actual malicious addons) If you want the extension without flipping the about:config entry. You can open up the extension in something that can handle zip files, edit install.rdf, and change the extension id to something else. Of course that will need to be done for every update of said extension.