This would allow wallet operations like funding transactions with smart contract-based inputs such as LN, or any input the Core wallet doesn't know how to sign for.

https://github.com/bitcoin/bitcoin/pull/17211#issuecomment-933674310
{"inputs", RPCArg::Type::ARR, RPCArg::Optional::OMITTED_NAMED_ARG, "Leave empty to add inputs automatically. See add_inputs option.",
                        {
                            {"", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "",
                                {
                                    {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The transaction id"},
                                    {"vout", RPCArg::Type::NUM, RPCArg::Optional::NO, "The output number"},
                                    {"sequence", RPCArg::Type::NUM, RPCArg::DefaultHint{"depends on the value of the 'locktime' and 'options.replaceable' arguments"}, "The sequence number"},
                                },
                            },
                        },
                        },
                    {"outputs", RPCArg::Type::ARR, RPCArg::Optional::NO, "The outputs (key-value pairs), where none of the keys are duplicated.\n"
                            "That is, each address can only appear once and there can only be one 'data' object.\n"
                            "For compatibility reasons, a dictionary, which holds the key-value pairs directly, is also\n"
                            "accepted as second parameter.",
                        {
                            {"", RPCArg::Type::OBJ_USER_KEYS, RPCArg::Optional::OMITTED, "",
                                {
                                    {"address", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "A key-value pair. The key (string) is the bitcoin address, the value (float or string) is the amount in " + CURRENCY_UNIT + ""},
                                },
                                },
                            {"", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "",
                                {
                                    {"data", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "A key-value pair. The key must be \"data\", the value is hex-encoded data"},
                                },
                            },
                        },
                    },
                    {"locktime", RPCArg::Type::NUM, RPCArg::Default{0}, "Raw locktime. Non-0 value also locktime-activates inputs"},
                    {"options", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED_NAMED_ARG, "",