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For that page Martin and I think it's a bug, however we disagree whose bug it is, validator or XML 1.0 3rd/4th edition. It could be also no bug at all if... %D0%B8%D1%81%D0%BF%D1%8B%D1%82%D0%B0%D0%BD%D0%B8%D0%B5.boldlygoingnowhere.org ...is a valid <reg-name> in some non-DNS-based parallel universe.