I booted my Win 10 today and started Firefox. All of a sudden I got the "warning" in the title. The add-on was Search and New Tab by Yahoo. I looked in my installed applications and right at the bottom I had a newly installed application called Yahoo Search Set. Needless to say I didn't install it.
The problem with the message above is that it doesn't provide enough information about who's trying to install the add-on. Yes, in this case I got it right but what are the chances of an adware or other malicious piece of software (I view Yahoo Search Set as well as the Firefox add-on as such since it installed without me saying so) announcing itself in a clear way?
Is there a way to find who is trying to add something new to Firefox (or any other mainstream browser for that matter)?