| Source Element | Usage | Target |
|---|---|---|
| BackboneType | UseExtension | http://hl7.org/fhir/5.0/StructureDefinition/extension-BackboneType |
| BackboneType.id | UseExtensionFromAncestor | - |
| BackboneType.extension | UseExtensionFromAncestor | - |
| BackboneType.modifierExtension | UseExtensionFromAncestor | - |