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
UniValue result_errors(UniValue::VARR);
    for (const bilingual_str& error : errors) {
        result_errors.push_back(error.original);
    }
    result.pushKV("errors", result_errors);
    return result;
},
    };
}
RPCHelpMan bumpfee() { return bumpfee_helper("bumpfee"); }
RPCHelpMan psbtbumpfee() { return bumpfee_helper("psbtbumpfee"); }
RPCHelpMan send()
{
    return RPCHelpMan{"send",
        "\nEXPERIMENTAL warning: this call may be changed in future releases.\n"
        "\nSend a transaction.\n",
        {
            {"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 convenience, a dictionary, which holds the key-value pairs directly, is also accepted.",
                {
                    {"", 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"},
                        },