[mkl]

Are you sure? When I type https://xn--971h.com in it doesn't work, but clicking the link in your comment does because HN has made the href x.com. The browser converts 𝕏.com to x.com before going there too. Moreover, X and 𝕏 are treated as equivalent characters in this context, so whois 𝕏.com looks up x.com, and 𝕏.com's punycode encoding is x.com: https://www.whatsmydns.net/idn-punycode-converter?q=%F0%9D%9...

whois xn--971h.com returns the same thing as an unregistered domain.

[jonas-w]

HN automatically converts these urls to punycode, maybe this is a bug and it automatically converts everything to punycode even though it doesn't make sense?

[yreg]

It's unrelated to HN. Copy pasting 𝕏.com into the address bar still leads to x.com

related: https://en.wikipedia.org/wiki/IDN_homograph_attack

[mkl]

I already mentioned that, and it's not what they mean. Hover your mouse over a https://xn--971h.com link in a comment on HN and notice that it's pointing to https://x.com. This does seem to be an HN thing; see here: https://jsfiddle.net/rtfhejdy/

[mkl]

I think so. Then I'm not right about the punycode encoding of 𝕏.com - it's that it isn't even needed. I've emailed dang about it.

[dom96]

Looks like it's also not possible to register xn--971h.com (I tried both Namecheap and Cloudflare).

[mikea1]

Yeah, it's explicitly disallowed by ICANN to register a domain with this unicode character (along with numerous other characters):

https://www.verisign.com/assets/icannrestricted/idn-icann-re...