Saxon implements the xsl:import-schema declaration in the schema-aware
product Saxon-SA only.
The namespace attribute specifies the target namespace of the schema to be
imported. The attribute should be omitted when importing a schema with no target namespace.
The schema-location attribute specifies where the schema document can be
found. This URI is passed through the URIResolver in the same way as the URIs used on
xsl:include and xsl:import. The attribute can be omitted only if
a schema for the required namespace has already been loaded in the Configuration,
for example if it has already been imported from another stylesheet module.
For further information see Schema Processing.
