The public suffix list currently isn’t done at the DNS level or the HTTP level—rather it’s a hard-coded list that all the browsers copy. If I were redesigning

The public suffix list currently isn’t done at the DNS level or the HTTP level—rather it’s a hard-coded list that all the browsers copy. If I were redesigning whatever I felt like without backwards-compatibility concerns, things like TLS certificate authentication, HTTP Strict Transport Security and public suffix matters would certainly all be done through DNS. Not sure if anyone has ever seriously suggested shifting the PSL into DNS, but it seems a pretty reasonable goal to me. Certainly a few other things of this general style (that is, things you need to know before making the HTTPS connection) have been shifting into DNS, and a public suffix list is a better candidate than most because it’s a comparatively restricted set of people that will be using it, so they can cope with setting DNS records (that is, you’re not pushing everyone into implementing it, which would be completely doomed to failure).