IdentFavIcon Quantum от Wolfgang Faust

This extension generates recognizable icons for webpages that don't specify a favicon. The icon generated is unique to each domain. The extension requires no configuration; just visit a site with no favicon and you should see the generated icon in the tab header. (Note: when the extension is disabled or removed, open tabs will keep the generated favicon until they're refreshed. This is because it can't unset the icon during uninstallation.)

This is the spiritual successor to the original IdentFavIcon Firefox extension, which unfortunately doesn't work on Firefox 57+ (Quantum). It doesn't use the same method of generating icons, mostly because I couldn't be bothered to figure out the code from the original addon. (Patches for this would be appreciated.)

KNOWN BUG: Sometimes sites have their favicon overridden even when they already provide one. The underlying bug in Firefox is bug 1417721 ; please vote on that issue to help get this fixed! In the meantime there are some workarounds implemented in the extension to mitigate the issue, but they're not 100% reliable. I apologize for any inconvenience.