http://hl7.org/fhir/StructureDefinition/workflow-instantiatesUri|4.0.1

The URL pointing to an externally maintained protocol, guideline, orderset or other definition that is adhered to in whole or in part by the event or request resource.
typedestination
baseDefinitionhttp://hl7.org/fhir/StructureDefinition/Extension
typehttp://hl7.org/fhir/StructureDefinition/Extension
Extension.value[x].typehttp://hl7.org/fhir/StructureDefinition/uri