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.
{ "setwalletflag", 1, "value" },
    { "getmempoolancestors", 1, "verbose" },
    { "getmempooldescendants", 1, "verbose" },
    { "gettxspendingprevout", 0, "outputs" },
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    { "bumpfee", 1, "conf_target"},
    { "bumpfee", 1, "fee_rate"},
    { "bumpfee", 1, "replaceable"},
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    { "psbtbumpfee", 1, "options" },
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    { "psbtbumpfee", 1, "fee_rate"},
    { "psbtbumpfee", 1, "replaceable"},
    { "psbtbumpfee", 1, "outputs"},
    { "logging", 0, "include" },
    { "logging", 1, "exclude" },
    { "disconnectnode", 1, "nodeid" },
    { "upgradewallet", 0, "version" },
    
    { "echojson", 0, "arg0" },
    { "echojson", 1, "arg1" },
    { "echojson", 2, "arg2" },
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    { "rescanblockchain", 0, "start_height"},