description: External Identifiers associated with this element - these are identifiers that are associated with the concept this element represents. package_name: rs/hl7.fhir.uv.extensions.r4 derivation: constraint name: Identifier type: Extension elements: extension: {index: 0} url: pattern: {type: uri, value: 'http://hl7.org/fhir/StructureDefinition/elementdefinition-identifier'} type: uri index: 1 value: choices: [valueIdentifier] index: 3 valueIdentifier: {type: Identifier, choiceOf: value, index: 4} package_version: 5.1.0 extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/elementdefinition-identifier base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.1.0 required: [value, valueIdentifier]