Union of http://hl7.org/fhir/StructureDefinition/structuredefinition-hierarchy and http://hl7.org/fhir/StructureDefinition/structuredefinition-hierarchy

This is the set of resources that conform to either of the profiles StructureDefinition Hierarchy (http://hl7.org/fhir/StructureDefinition/structuredefinition-hierarchy) and StructureDefinition Hierarchy (http://hl7.org/fhir/StructureDefinition/structuredefinition-hierarchy). E.g. what you have to deal with if you get resources conforming to one of them

Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. Extension 0..1Whether a circular reference is allowed to (transitively) point back to the same instance
ele-1: All FHIR elements must have a @value or children
ext-1: Must have either extensions or value[x], not both
... url 1..1uriidentifies the meaning of the extension
... value[x] 1..1booleanValue of extension
ele-1: All FHIR elements must have a @value or children

doco Documentation for this format