core-lightning/doc/schemas/txprepare.schema.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "required": [
    "psbt",
    "unsigned_tx",
    "txid"
  ],
  "properties": {
    "psbt": {
      "type": "string",
      "description": "the PSBT representing the unsigned transaction"
    },
    "unsigned_tx": {
      "type": "hex",
      "description": "the unsigned transaction"
    },
    "txid": {
      "type": "txid",
      "description": "the transaction id of *unsigned_tx*; you hand this to lightning-txsend(7) or lightning-txdiscard(7), as the inputs of this transaction are reserved."
    }
  }
}