http://hl7.org/fhir/StructureDefinition/iso21090-preferred|4.0.1

Flag denoting whether parent item is preferred - e.g., a preferred address or telephone number.

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