I have a small problem when adding an umlaut domain to a repository.
Let’s take any domain as an example:
häuser .de
is the same as
xn–huser-gra .de
but in gitlab pages I can only store the xn domain. In the case of the umlauts, it says “Domain contains invalid characters (valid characters: [a-z0-9-])”.
A browser would normally convert an ä to ae - therefore you could use haeuser.de instead since if Gitlab pages only supports [a-z0-9] that means you cannot use letters with umlauts, etc, and you will need to utilise that as a workaround. At least until systems are configured to support non-standard characters such as umlauts in domain names.
What does work is using the ACE string of the IDN Domain Name. The ACE string only contains the letters a-z, A-Z and -, for example, for the domain überall-ist.de, it is xn--berall-ist-8db.de. If you paste the ACE string into your browser URL input and press enter, the URL changes to überall-ist.de.