Ok I didn't know about this list. Feel like I should have known! I always though it was up to countries and top-level operators. I imagined something like .uk publishing somehow that .co.uk is a top level domain, for example.

I think the requirements to run a top level domain, like .lol itself are pretty onerous? But I wonder if it is easier to get your subdomain added to the public suffix list, and I wonder what legal guarantees are afforded to someone who registers such a domain.