finalizepsbt "psbt" ( extract )
Finalize the inputs of a PSBT. If the transaction is fully signed, it will produce a
network serialized transaction which can be broadcast with sendrawtransaction. Otherwise a PSBT will be
created which has the final_scriptSig and final_scriptWitness fields filled for inputs that are complete.
Implements the Finalizer and Extractor roles.

1. "psbt" (string) A base64 string of a PSBT
2. "extract" (boolean, optional, default=true) If true and the transaction is complete,
extract and return the complete transaction in normal network serialization instead of the PSBT.

"psbt" : "value", (string) The base64-encoded partially signed transaction if not extracted
"hex" : "value", (string) The hex-encoded network transaction if extracted
"complete" : true|false, (boolean) If the transaction has a complete set of signatures

> bitcoin-cli finalizepsbt "psbt"
Don't trust. Verify. Docs extracted from src/rpc/rawtransaction.cpp#L1610-L1634.