{
  "resourceType": "StructureDefinition",
  "url": "https://example.org/fhir/StructureDefinition/MyExtensionTracey",
  "name": "MyExtensionTracey",
  "status": "draft",
  "fhirVersion": "4.0.1",
  "kind": "complex-type",
  "abstract": false,
  "type": "Extension",
  "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension",
  "derivation": "constraint",
  "differential": {
    "element": [
      {
        "id": "Extension.url",
        "path": "Extension.url",
        "fixedUri": "https://example.org/fhir/StructureDefinition/MyExtensionTracey"
      }
    ]
  }
}