http://hl7.org/fhir/StructureDefinition/elementdefinition-graphConstraint|5.2.0

Will cause a GraphDefinition to be executed and the referred-to instance be considered \"valid\" for that GraphDefinition if the instance is the start of a result of executing that GraphDefinition.
typedestination
baseDefinitionhttp://hl7.org/fhir/StructureDefinition/Extension
typehttp://hl7.org/fhir/StructureDefinition/Extension
Extension.value[x].typehttp://hl7.org/fhir/StructureDefinition/canonical
Extension.value[x].targetProfilehttp://hl7.org/fhir/StructureDefinition/GraphDefinition