Context: Assume a situation where a favicon coming from another domain (or subdomain) is used, as so:

By default, the favicon will not work, because of a Content-Security-Policy error:

Of course, an evident workaround is to manually add img-src other-website.com in the security.content_security_policy value, in the Config. But that additional step can confuse people.

So, I wonder if snappymail could automatically add the domain where the favicon is under as an allowed img-src automatically.