xsi:schemaLocation (continued)

As well as an xsi:schemaCatalog attribute, I would suggest an attribute
whose value is the URI reference of the "no namespace" schema (eg
xsi:defaultSchemaLocation).  My thinking is that the mapping from
namespace URIs to schema URIs is likely to be shareable amongst multiple
documents, whereas the "no namespace" schema is likely to vary from
document to document.

James