A bit late to the party, but I just tried #12653 and noticed some non-intuitive behavior (on macOS), that's probably worth explaining release notes and help.

Before this new feature I kept the entire datadir on an SSD drive, so I launch with: `bitcoind -datadir=/Volumes/SSD/Bitcoin`.

Initially I naively moved `/Volumes/SSD/Bitcoin/blocks` to `/Users/bitcoin/blocks` and added a line to `/Volumes/SSD/Bitcoin/bitcoin.conf`: `blocksdir=/Users/bitcoin/blocks`.

I then realized that I shouldn't have moved the `index` subdirectory, so I moved that back to `/Volumes/SSD/Bitcoin/blocks/index`. Having an empty `blocks` dir with just and `index` subdir is a bit weird. Perhaps after @jimpo's #11857 is merged, we could just move / assume all indexes to be there (if `-blocksdir` is set)?

Worse, it created a directory `/Users/bitcoin/blocks/blocks`, which seems like a bug. I had to set `blocksdir=/Users/bitcoin` instead.
}
            proxyType addrOnion = proxyType(onionProxy, proxyRandomize);
            if (!addrOnion.IsValid())
                return InitError(strprintf(_("Invalid -onion address or hostname: '%s'"), onionArg));
            SetProxy(NET_ONION, addrOnion);
            SetLimited(NET_ONION, false);
        }
    }
    
    fListen = gArgs.GetBoolArg("-listen", DEFAULT_LISTEN);
    fDiscover = gArgs.GetBoolArg("-discover", true);
    fRelayTxes = !gArgs.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY);
    for (const std::string& strAddr : gArgs.GetArgs("-externalip")) {
        CService addrLocal;
        if (Lookup(strAddr.c_str(), addrLocal, GetListenPort(), fNameLookup) && addrLocal.IsValid())
            AddLocal(addrLocal, LOCAL_MANUAL);
        else
            return InitError(ResolveErrMsg("externalip", strAddr));
    }
#if ENABLE_ZMQ
    g_zmq_notification_interface = CZMQNotificationInterface::Create();
    if (g_zmq_notification_interface) {
        RegisterValidationInterface(g_zmq_notification_interface);
    }
#endif
    uint64_t nMaxOutboundLimit = 0; 
    uint64_t nMaxOutboundTimeframe = MAX_UPLOAD_TIMEFRAME;
    if (gArgs.IsArgSet("-maxuploadtarget")) {
        nMaxOutboundLimit = gArgs.GetArg("-maxuploadtarget", DEFAULT_MAX_UPLOAD_TARGET)*1024*1024;
    }