curl --request GET \
  --url https://api.projectcor.com/v1/projects/{project_id}/labels \
  --header 'Authorization: Bearer <token>'

{
  "labels": [
    {
      "id": 123,
      "name": "<string>",
      "labels": [
        {
          "id": 123,
          "hex": "<string>",
          "hsl": "<string>",
          "rgb": "<string>",
          "lang": "<string>",
          "name": "<string>",
          "color_id": 123
        }
      ]
    }
  ],
  "selected": [
    {
      "id": 123,
      "hex": "<string>",
      "hsl": "<string>",
      "rgb": "<string>",
      "lang": "<string>",
      "name": "<string>",
      "color_id": 123
    }
  ]
}