Who is in charge of XML?
XML is a W3C Recommendation
The W3C is The World Wide Web Consortium, a voluntary association of companies and non-profit organisations. Membership costs serious money, confers voting rights. Complex procedures, with the Chairman (Tim Berners-Lee) holding all the high cards, but the big vendors (e.g. Microsoft, Adobe, Netscape) have a lot of power.
The XML recommendation was written by the W3Cís XML Working Group.