What you&#x27;re saying is true, but in the context of CAs, it&#x27;s still important to be able to distinguish <i>real</i> public suffixes from regular authority delegations for subdomains. CAs need to be able to filter and block CSRs for wildcard names like *.co.uk or something similar. This also applies to things like cookie scopes in browsers. Currently, the Public Suffix List is your best bet here.<p>The Dbound WG[1] is working towards a standardized solution that doesn&#x27;t require enumeration in a centralized list but rather works through DNS records. This should eventually replace the PSL, although I suspect most use cases will still rely on some kind of preload list (similar to HSTS) in addition to that.<p>[1]: <a href="https:&#x2F;&#x2F;tools.ietf.org&#x2F;wg&#x2F;dbound&#x2F;" rel="nofollow">https:&#x2F;&#x2F;tools.ietf.org&#x2F;wg&#x2F;dbound&#x2F;</a>