xlink:show

<attribute name="show">
  <simpleType>
    <annotation>
      <documentation>Enumeration of values for the show attribute</documentation>
    </annotation>
    <restriction base="string">
      <enumeration value="new"/>
      <enumeration value="replace"/>
      <enumeration value="embed"/>
      <enumeration value="other"/>
      <enumeration value="none"/>
    </restriction>
  </simpleType>
</attribute>