http://hl7.org/fhir/StructureDefinition/questionnaireresponse-author|5.2.0

Allows capturing, on a specific question or group of questions, exactly who was responsible for providing the answer(s).

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