The PatternFeatureNominalBaseType is the abstract base type that defines the pattern feature nominal information for an individual pattern feature. Each feature nominal in an instance of PatternFeatureNominalBaseType must reference the same feature definition.
The id attribute is the QIF id of the feature, used for referencing.
Source
<xs:complexType name="PatternFeatureNominalBaseType" abstract="true"><xs:annotation><xs:documentation>The PatternFeatureNominalBaseType is the abstract base type that defines the pattern feature nominal information for an individual pattern feature. Each feature nominal in an instance of PatternFeatureNominalBaseType must reference the same feature definition.</xs:documentation></xs:annotation><xs:complexContent><xs:extension base="GroupFeatureNominalType"/></xs:complexContent></xs:complexType>