I use an extension called new xkit (for tumblr) from here: https://github.com/new-xkit/XKit/wiki/Installing-XKit#firefox (not the one listed in your extensions search, not the same). The icon for this no longer shows up by itself on my toolbar--but under the puzzle piece. This means that I can NO LONGER MODIFY ANYTHING in the extension. I need to have it on the toolbar, so that I can modify it--and I'm not talking about manage extensions. UBlock origin still shows up there because you need to be able to adjust it. Same thing with New xkit. You've actually broken the extension because it's not working on tumblr anymore. This needs to be fixed.