[XHTML 2] Section 3.1.1

Dear HTML Working Group,

Item 3 of section 3.1.1 says
"The start tag must also contain an xsi:schemaLocation attribute. The schema 
location for XHTML 2.0 is defined to be 
http://www.w3.org/MarkUp/SCHEMA/xhtml2.xsd."

This is unclear, does it say that the start tag must contain an 
xsi:schemalLocation attribute with the value of 
"http://www.w3.org/MarkUp/SCHEMA/xhtml2.xsd" or is the information about 
that value purely informative of a suitable value, and other possible 
schemas may be used instead?

Please clarify the specification to make it clear which is correct.

Regards,

Jim Ley.