<xsd:element name="proprietary">
  <xsd:annotation>
    <xsd:documentation>
      <type>Element</type>
      <name>proprietary</name>
      <comment>The element proprietary is a metadata container of any additional metadata property that does not belong to the Akoma Ntoso properties. Anything can be placed in this element.</comment>
    </xsd:documentation>
  </xsd:annotation>
  <xsd:complexType>
    <xsd:complexContent>
      <xsd:extension base="anyOtherType">
        <xsd:attributeGroup ref="source"/>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>
</xsd:element>