Just saw this about a proof-of-concept for using favicons as a supercookie:
I did some searching and found this possible countermeasure, which is just turning off favicons. IDK if it’s sufficient or just keeps it from showing the favicon but still sends the GET request that allows the tracking? I think we can/should also delete the favicon cache?
Is that like the Facebook thumbs up/Twitter bird/ Google G+ picture, but for other companies?
It’s that little picture that shows up in your tab and in your bookmarks.
Oh, that’s not good. If I read the article, does it say how to switch it off?
Or just manual entries from the OS hosts file?
Not even in the hosts file cuz they come right from the host and can have different file names. 
Here’s some background info on favicons:
Oh, I never heard of that one so IDK?
Firefox has this about their version 85 helping thwart supercookies, but doesn’t say anything about the favicons:
Honestly surprised this only comes up now and not years ago…
I have found evidence of people abusing this for years.
I literally thought that’s probably what they were invented for?