@emarci You misconstrued my comment. I completely understand what the "firefox addons" test case requires. I don't believe it belongs here. We're testing Firefox, not the addons. As I mentioned in my previous comment, probably not appropriate hold up stable release of the browser because addon xyz isn't working.
Don't use the Fedora addons, prefer to download addons directly from addons.mozilla.org (which btw has been redesigned for Fx 57). Must easier to find what you want and check compatibility, etc. and get timely updates. Probably not appropriate hold up stable release of the browser because addon xyz isn't working.