xlink:extended 

Intended for use as the type of user-declared elements to make them extended links. Note that the elements referenced in the content model are all abstract. The intention is that by simply declaring elements with these as their substitutionGroup, all the right things will happen.

Complex Type Information

Model

xlink:title | xlink:resource | xlink:locator | xlink:arc
Children: xlink:arc, xlink:locator, xlink:resource, xlink:title

Attributes

QName Type Fixed Default Use Inheritable Annotation
xlink:role xlink:roleType optional
xlink:title xlink:titleAttrType optional
xlink:type xlink:typeType extended required

Source 

<xs:complexType name="extended">
  <xs:annotation>
    <xs:documentation>Intended for use as the type of user-declared elements to make them extended links. Note that the elements referenced in the content model are all abstract. The intention is that by simply declaring elements with these as their substitutionGroup, all the right things will happen.</xs:documentation>
  </xs:annotation>
  <xs:group ref="xlink:extendedModel" minOccurs="0" maxOccurs="unbounded"/>
  <xs:attributeGroup ref="xlink:extendedAttrs"/>
</xs:complexType>