The global FeatureZone element is the head of a substitution group. Any element that is a member of this group may be substituted for the FeatureZone element anywhere the FeatureZone element may be used in an instance file.
The id attribute is the QIF id of the feature zone, used for referencing.
Source
<xs:element name="FeatureZone" type="FeatureZoneBaseType" abstract="true"><xs:annotation><xs:documentation>The global FeatureZone element is the head of a substitution group. Any element that is a member of this group may be substituted for the FeatureZone element anywhere the FeatureZone element may be used in an instance file.</xs:documentation></xs:annotation></xs:element>