The InternalExternal element indicates whether the feature is internal or external. For example, an edge point on the edge of a desk would be external, and an edge point where a floor meets a wall would be internal.
<xs:element name="InternalExternal" type="InternalExternalEnumType"><xs:annotation><xs:documentation>The InternalExternal element indicates whether the feature is internal or external. For example, an edge point on the edge of a desk would be external, and an edge point where a floor meets a wall would be internal.</xs:documentation></xs:annotation></xs:element>
The id attribute is the QIF id of the feature, used for referencing.
Source
<xs:complexType name="EdgePointFeatureDefinitionType"><xs:annotation><xs:documentation>The EdgePointFeatureDefinitionType defines the edge-point feature nominal information that can be common to one or more edge point features.</xs:documentation></xs:annotation><xs:complexContent><xs:extension base="PointFeatureDefinitionBaseType"><xs:sequence><xs:element name="InternalExternal" type="InternalExternalEnumType"><xs:annotation><xs:documentation>The InternalExternal element indicates whether the feature is internal or external. For example, an edge point on the edge of a desk would be external, and an edge point where a floor meets a wall would be internal.</xs:documentation></xs:annotation></xs:element></xs:sequence></xs:extension></xs:complexContent></xs:complexType>