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

Represents the routing information such as a letter carrier route number. It is the identifying number of the designator (the box number or rural route number).
typedestination
baseDefinitionhttp://hl7.org/fhir/StructureDefinition/Extension
typehttp://hl7.org/fhir/StructureDefinition/Extension
Extension.value[x].typehttp://hl7.org/fhir/StructureDefinition/string