<!ELEMENT extension (pattern+ | category+ | descriptionSource+)>
<!ATTLIST extension
point CDATA #REQUIRED
id CDATA #IMPLIED
name CDATA #IMPLIED
>
<!ELEMENT pattern EMPTY>
<!ATTLIST pattern
class CDATA #REQUIRED
>
<!ELEMENT category EMPTY>
<!ATTLIST category
id CDATA #REQUIRED
path CDATA #REQUIRED
name CDATA #REQUIRED
>
<!ELEMENT descriptionSource EMPTY>
<!ATTLIST descriptionSource
class CDATA #REQUIRED
>