ded:Definition: An attribute of source that
specifies the schema type used to identify the format of the
resource.
ded:Obligation: (Optional)
ded:Comment: If a schema defines the format of the data asset, then this
element should be used. For example, if the data asset is an XML document
that conforms to an XML Schema document then this element would contain the
value "XSD". Other possible values may include RNG, WSDL, SQL,
etc.