That or whitelist specific characters based on the users locale. E.g. on a system set to german I could expect umlauts and ß to be rendered properly, but anythi

That or whitelist specific characters based on the users locale. E.g. on a system set to german I could expect umlauts and ß to be rendered properly, but anything else should just show the punycode. Basically any legitimate use case should be covered by that.