This work is licensed under the Creative Commons Attribution-ShareAlike
License. To view a copy of this license, see the file license.txt,
visit http://creativecommons.org/licenses/by-sa/2.0 or send a letter to
Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
This component schema definition provides the element group declaration and the
attribute group declaration used for extension XML elements and attributes.