curl --request GET \
  --url https://{host}/api/v3/departments/tree \
  --header 'Authorization: <authorization>'

{
  "data": {
    "node": "<unknown>",
    "children": [
      {
        "node": {
          "id": 123,
          "name": "<string>",
          "url": "<string>"
        },
        "children": [
          {}
        ]
      }
    ]
  }
}