Google provides a favicon-fetching (cached usually) API, allowing size (sz) and domain (url) (possibly others but at least these two should be allowed, possible trim domain). The API is called Shared Stuff (s2).
I'm using .google./^/s2/favicons$ with allow-list domain and sz.
Google is often used as a favicon cache for websites and tools. It probably could use an allow-listing.
Example: https://www.google.com/s2/favicons?domain=www.virustotal.com&sz=64 https://www.virustotal.com/
Google provides a favicon-fetching (cached usually) API, allowing size (sz) and domain (url) (possibly others but at least these two should be allowed, possible trim domain). The API is called Shared Stuff (s2).
I'm using .google./^/s2/favicons$ with allow-list domain and sz.