XML Schema 1.0 implementation
A restriction has been lifted: fixed and default values are now supported
for elements with a complex type (specifically, a complex type with mixed content).
A SchemaURIResolver may now be specified for resolving the location hints found in
xsd:import, xsd:include, and xsd:redefines; in the
xsi:schemaLocation and xsi:noNamespaceSchemaLocation attributes in instance
documents; in the xsl:import-schema declaration in XSLT; and in the import schema
declaration in XQuery. This differs from a normal URIResolver in that the decision may be made
based both on the target namespace of the schema being loaded, and on the location hints.
It is no longer an error for schema documents to include each other recursively. This condition now results in a warning message rather than an error message.