Never works. Maybe I'm not using it properly but I didn't get/don't see any instructions. I assume that to generate an alias I just click on an email field then click on the Firefox Relay icon, a bar appears and looks like it's searching/preparing/generating - whatever - but nothing actually happens. It might be restrained by other popup/block extensions but I don't want to have to spend time figuring that out. I just expect it to do what it says it does.