xsl:method

<xs:simpleType name="method">
  <xs:annotation>
    <xs:documentation>The method attribute of xsl:output: Either one of the recognized names "xml", "xhtml", "html", "text", or a QName that must include a prefix.</xs:documentation>
  </xs:annotation>
  <xs:union>
    <xs:simpleType>
      <xs:restriction base="xs:NCName">
        <xs:enumeration value="xml"/>
        <xs:enumeration value="xhtml"/>
        <xs:enumeration value="html"/>
        <xs:enumeration value="text"/>
      </xs:restriction>
    </xs:simpleType>
    <xs:simpleType>
      <xs:restriction base="xsl:QName">
        <xs:pattern value="\c*:\c*"/>
      </xs:restriction>
    </xs:simpleType>
  </xs:union>
</xs:simpleType>