.co.uk is run by the same people as .uk. There is no additional org that you trust when you register a .co.uk: https://en.wikipedia.org/wiki/.uk#Second-level_domains

> do browsers have a wildcard suffix list

Yes: https://publicsuffix.org/ and they have discussed this situation here: https://github.com/publicsuffix/list/issues/2306

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akersten 3 hours ago | parent | next [-]

I know about the public suffix list - I was wondering about the wildcard specifically. In the very issue you linked to, as of 2025, it seems this was still unresolved...:

> We have no plans to modify the .name entries at this point in time. We are aware of the implications of adding a wildcard, therefore we won't.

	▲	xg15 an hour ago \| parent \| next [-]
		Yeah, apparently they both (used to) offer unbounded registrations of 3LDs and unbounded registrations of 2LDs? So if I see j.doe.name, the only way to find out if "doe.name" is a public suffix or not, i.e. if I should (not) be able to set a cookie on it, would be to email the registrar? So does that mean that in practice, .name domains were always treated by browsers like regular 2LDs, meaning the cookie and origin protection was always broken for those domains? Doesn't sound like good news for the guy in the OP...
	▲	SahAssar 2 hours ago \| parent \| prev [-]
		I'm just saying that they have discussed the situation. They seem to have no answer and for cookies and similar things the answer probably is "maybe don't run security critical web stuff in the third level under .name". IIRC orgs like letsencrypt also use the PSL for rate limits, so there are probably more issues that are not browser-based.

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eloisant 2 hours ago | parent | prev [-]

Yes, Japan does the same with .co.jp but also .ne.jp, ac.jp, etc.

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adw 2 hours ago | parent [-]

There are many examples; k12.<state>.us is another.

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marcosdumay 2 hours ago | parent | next [-]

It is (or was for a long time, IDK) a strongly recommended practice from ICANN. I imagine nearly all countries to do that.

	▲	dhosek an hour ago \| parent [-]
		There end up being some weird edge cases where there are some countries which have both the equivalent of .co.uk but also allow registrations directly under the two-letter country code as well. .mx is one such case where most business are, e.g., costco.com.mx, but it’s also possible to register directly under .mx as well so Toyota Mexico is toyota.mx and not toyota.com.mx (the latter is registered, and ostensibly to Toyota, but the whois and nslookup records give very different results and the website doesn’t load when I try to visit it).

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eloisant 36 minutes ago | parent | prev [-]

Except nobody uses the .us tld, but pretty much every every Japanese company is on a .co.jp