curl --request GET \
  --url https://{workspaceId}.clinia.cloud/sources/{sourceKey}/v1/relationship-definitions \
  --header 'X-Clinia-API-Key: <api-key>'

{
  "meta": {
    "numPages": 123,
    "page": 123,
    "perPage": 123,
    "total": 123
  },
  "data": [
    {
      "key": "<string>",
      "from": {
        "profileKey": "<string>",
        "includeKey": "<string>",
        "includeCardinality": "0:*"
      },
      "to": {
        "profileKey": "<string>",
        "includeKey": "<string>",
        "includeCardinality": "0:*"
      },
      "description": "<string>",
      "properties": {}
    }
  ]
}