curl --request GET \
  --url https://tonapi.io/v2/rewards/validation-rounds

{
  "response_time_ms": 1234,
  "rounds": [
    {
      "election_id": 1740053384,
      "start_block": 57480000,
      "finished": true,
      "start_utime": 23814011000000,
      "end_utime": 23814011000000,
      "end_block": 57546000,
      "prev_election_id": 1772486024,
      "next_election_id": 1772658824,
      "total_stake": 123456789,
      "bonuses": 123456789
    }
  ]
}

{
  "error": "<string>",
  "error_code": 123,
  "details": {
    "required": 123,
    "available": 123
  }
}