http://hl7.org/fhir/StructureDefinition/data-absent-reason|4.0.1

Provides a reason why the expected value or elements in the element that is extended are missing.

element_id	types
Extension
Extension.extension
Extension.url
Extension.value[x]	code
Extension
Extension.id	http://hl7.org/fhirpath/System.String
Extension.extension	Extension
Extension.url	http://hl7.org/fhirpath/System.String
Extension.value[x]	code