Define this for schema components that have back-references to ref objects.
Define this for schema components that have back-references to ref objects. So group def to group ref, globalelementdecl to element ref, type to element, base type to derived type.
Not for format annotations however. We don't backpoint those to other format annotations that ref them.
The lexically enclosing schema component
The enclosing component, and follows back-references from types to their elements, from globalElementDef to elementRefs, from simpleType defs to derived simpletype defs, from global group defs to group refs
The enclosing component, and follows back-references from types to their elements, from globalElementDef to elementRefs, from simpleType defs to derived simpletype defs, from global group defs to group refs
Note: the enclosing component of a global element or global group referenced from a element ref or group ref, is NOT the ref object, but the component that contains the ref object