IDNA
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... treating the HostName as a "query string" (i.e., the AllowUnassigned
flag MUST be set). Note that IDNA allows labels to be separated by
any of the Unicode characters U+002E, U+3002, U+FF0E, and U+FF61;
...
... Faltstrom, P., Hoffman, P., and A. Costello, "Internationalizing Domain Names in Applications (IDNA)", RFC 3490prop, March 2003. ...