This isn't related to the post content (which was great), but I noticed that HN lists the domain as "surge.sh", which doesn't make a lot of sense because surge.sh is just the web hosting service this site is on.
With the web, the convention right now is to treat the subdomain as a different security origin (with the exception of www). So the link should show c0ffee.surge.sh, not surge.sh.
If this is a manual setting, it probably also needs to be set for neocities.org. I noticed that wordpress.com domains were being subdomained properly.
It really shouldn't be manual, it should just always show the correct origin domain.
I was warned to not use it by it's maintainers because it would make the root of our domain potentially unusable. If I understand it correctly, it's designed for things like domain roots (.com), not domains with subdomains.
It is useful for some security protections in such a hosted subdomain scenario which is why herokuapp.com, herokussl.com, github.io, gitlab.io, etc are on the list, but yes, you would not be able to use your primary domain there, you'd need a dedicated domain for your customers and their subdomains.
Namely, having your hosting domain on the public suffix list means that browsers will not allow setting cookies on the suffix (similar to how you cannot set a cookie for ".com"), which prevents rogue websites on the same root domain from stealing sensitive cookie values from other subdomains.
You didn't read through far enough (or, more likely, you didn't ctrl-F well enough). After the "ICANN DOMAINS" section is the "PRIVATE DOMAINS" section. It contains entries like:
- s3.amazonaws.com
- blogspot.com
- githubusercontent.com
but there are many other sites in the list which are less notable.
Indeed, it doesn't really have anything to do with notability. You'll notice none of those root domains you just provided have sites attempting to use cookies on them.
With the web, the convention right now is to treat the subdomain as a different security origin (with the exception of www). So the link should show c0ffee.surge.sh, not surge.sh.
If this is a manual setting, it probably also needs to be set for neocities.org. I noticed that wordpress.com domains were being subdomained properly.
It really shouldn't be manual, it should just always show the correct origin domain.