http://hl7.org/fhir/StructureDefinition/practitioner-job-title|5.2.0

The job title may be independent of the role. For example, a surgeon (role) may have a title of Head of Surgery. Some titles may overlap with roles and could be represented as discrete PractitionerRoles, but some titles may be independent of role.
typedestination
baseDefinitionhttp://hl7.org/fhir/StructureDefinition/Extension
typehttp://hl7.org/fhir/StructureDefinition/Extension
Extension.value[x].typehttp://hl7.org/fhir/StructureDefinition/CodeableConcept
Extension.value[x].binding.valueSethttp://hl7.org/fhir/ValueSet/practitioner-job-title