v2.0 needs a redo Rated 1 out of 5 stars
As other posters have mentioned, v2.0 of this addon puts a non-removable icon in your browser status bar. At least if you have a third-party status bar addon installed; I use "Status-4-Evar" available on this site. It may do so even if you don't have such an addon.
You can "temporarily" get rid of it by opening Toolbars/Customize and dragging the icon to that panel. But on exiting and restart of Firefox, it automatically reappears again. There is no way to change this irritating conduct I've yet found.
This behavior is totally unlike what versions prior to 2.0 did. They did not automatically force an icon on you. No other addon I've tried (and that's been many) behaves this way.
Consequently, Addon Compatibility Reporter v2.0 is uninstalled here and I've recommended locally that all users who dislike this to do the same.
Hopefully future updates will remove this annoying problem.