description: An IANA timezone code for the timezone offset per [BCP 175](https://www.iana.org/go/rfc6557). The offset is specified as part of a dateTime/instant (or using the tzOffset extension on a date if necessary). The timezone code may also be provided to allow for human display of the location associated with the offset. package_name: hl7.fhir.uv.extensions derivation: constraint name: TimezoneCode type: Extension elements: extension: {index: 0} url: pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/tz-code'} index: 1 value: choices: [valueCode] index: 3 valueCode: {type: code, choiceOf: value, index: 4} package_version: 5.3.0-ballot extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/tz-code base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.3.0-ballot required: [valueCode, value]