This is an XML namespace identifier defined in the XForms 1.1 specification. The latest version can be found at: http://www.w3.org/TR/xforms11/
Until the specification reaches W3C Candidate Recommendation status, this namespace name may be reused by any update of the XForms 1.1 specification in such a way as to affect the operation of existing software written to process documents written according to this specification.
For more information about XForms, please refer to the W3C XForms overview.
For more information about XML, please refer to the Extensible Markup Language (XML) 1.0 specification. For more information about XML namespaces, please refer to the Namespaces in XML specification.