[uxp]

> whitelist the few that are actually real

I'm speculating that the balance is in the reverse favor. Last night I was looking at some file on GitHub which was redirecting to what looked like an S3 bucket subdomain named with a pattern like "github-production-f7e281a2", which I simply presumed to be cache-busting via subdomain instead of appending the hash to the filename. If my assumptions were correct, every time GitHub deploys a new build, you would have to whitelist that subdomain.