If I create an RBF transaction using the Qt GUI but specify my own custom change address, bumpfee doesn't work because it claims it can't find the change address:

    "Transaction does not have a change output"

This is because none of the outputs satisfy

    pWallet->IsChange(...)

I see there's a "TODO" commented in `CWallet::IsChange()` in `src/wallet/wallet.cpp`:

    // TODO: fix handling of 'change' outputs. The assumption is that any
    // payment to a script that is ours, but is not in the address book
    // is change.

I tend to put all my addresses in the address book whether I'm going to use them as change or not. I guess if the wallet was capable of creating its own SegWit change addresses I'd stop using custom change addresses, but currently it always seems to send change to a legacy address if I don't manually specify a change address.
}
        if (options.exists("changePosition") || options.exists("change_position")) {
            change_position = (options.exists("change_position") ? options["change_position"] : options["changePosition"]).getInt<int>();
        }
        if (options.exists("change_type")) {
            if (options.exists("changeAddress") || options.exists("change_address")) {
                throw JSONRPCError(RPC_INVALID_PARAMETER, "Cannot specify both change address and address type options");
            }
            if (std::optional<OutputType> parsed = ParseOutputType(options["change_type"].get_str())) {
                coinControl.m_change_type.emplace(parsed.value());
            } else {
                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Unknown change type '%s'", options["change_type"].get_str()));
            }
        }
        const UniValue include_watching_option = options.exists("include_watching") ? options["include_watching"] : options["includeWatching"];
        coinControl.fAllowWatchOnly = ParseIncludeWatchonly(include_watching_option, wallet);
        if (options.exists("lockUnspents") || options.exists("lock_unspents")) {
            lockUnspents = (options.exists("lock_unspents") ? options["lock_unspents"] : options["lockUnspents"]).get_bool();
        }
        if (options.exists("include_unsafe")) {
            coinControl.m_include_unsafe_inputs = options["include_unsafe"].get_bool();
        }
        if (options.exists("feeRate")) {
            if (options.exists("fee_rate")) {
                throw JSONRPCError(RPC_INVALID_PARAMETER, "Cannot specify both fee_rate (" + CURRENCY_ATOM + "/vB) and feeRate (" + CURRENCY_UNIT + "/kvB)");
            }
            if (options.exists("conf_target")) {
                throw JSONRPCError(RPC_INVALID_PARAMETER, "Cannot specify both conf_target and feeRate. Please provide either a confirmation target in blocks for automatic fee estimation, or an explicit fee rate.");
            }
            if (options.exists("estimate_mode")) {