match-attr
Specifies an attribute for create, placement, and matching rules.
When the <match-attr> element is specified in a <create-rule> or <placement-rule> element, at least one value must be specified.
When the <match-attr> element is specified in a <matching-rule> element, it must not contain a value.
<!ELEMENT match-attr (value)+ > <!ATTLIST match-attr attr-name CDATA #REQUIRED>