curl --request GET \
  --url https://test.deribit.com/api/v2/public/get_combo_details \
  --header 'Content-Type: application/json' \
  --data '
{
  "jsonrpc": "2.0",
  "id": 3,
  "method": "public/get_combo_details",
  "params": {
    "combo_id": "BTC-FS-29APR22_PERP"
  }
}
'

{
  "jsonrpc": "2.0",
  "id": 3,
  "result": {
    "state_timestamp": 1650620605150,
    "state": "active",
    "legs": [
      {
        "instrument_name": "BTC-PERPETUAL",
        "amount": -1
      },
      {
        "instrument_name": "BTC-29APR22",
        "amount": 1
      }
    ],
    "id": "BTC-FS-29APR22_PERP",
    "instrument_id": 27,
    "creation_timestamp": 1650620575000
  }
}