The required id attribute is the QIF id of the assignable cause, used for referencing.
Source
<xs:element name="AssignableCause" type="AssignableCauseType" maxOccurs="unbounded"><xs:annotation><xs:documentation>Each AssignableCause element gives information about the a particular assignable cause.</xs:documentation></xs:annotation></xs:element>
The required n attribute is the number of assignable causes in the list.
Source
<xs:complexType name="AssignableCausesType"><xs:annotation><xs:documentation>The AssignableCausesType defines a list of assignable causes.</xs:documentation></xs:annotation><xs:sequence><xs:element name="AssignableCause" type="AssignableCauseType" maxOccurs="unbounded"><xs:annotation><xs:documentation>Each AssignableCause element gives information about the a particular assignable cause.</xs:documentation></xs:annotation></xs:element></xs:sequence><xs:attribute name="n" type="NaturalType" use="required"><xs:annotation><xs:documentation>The required n attribute is the number of assignable causes in the list.</xs:documentation></xs:annotation></xs:attribute></xs:complexType>
<xs:attribute name="n" type="NaturalType" use="required"><xs:annotation><xs:documentation>The required n attribute is the number of assignable causes in the list.</xs:documentation></xs:annotation></xs:attribute>