`RewindBlockIndex` was made to allow nodes upgrading to new consensus rules post-segwit fork to 
download new consensus data (i.e witnesses) without having to go through a whole IBD. It has been pointed than now really few pre-segwit nodes care to upgrade and that this logic may be irrelevant.

See https://github.com/bitcoin/bitcoin/pull/17737#discussion_r358514335 in review  of #17737 for more context pointers.
RegisterZMQRPCCommands(tableRPC);
#endif
    /* Start the RPC server already.  It will be started in "warmup" mode
     * and not really process calls already (but it will signify connections
     * that the server is there and will be ready later).  Warmup mode will
     * be disabled when initialisation is finished.
     */
    if (args.GetBoolArg("-server", false)) {
        uiInterface.InitMessage_connect(SetRPCWarmupStatus);
        if (!AppInitServers(node))
            return InitError(_("Unable to start HTTP server. See debug log for details."));
    }
    
    for (const auto& client : node.chain_clients) {
        if (!client->verify()) {
            return false;
        }
    }
    
    
    
    
    
    fListen = args.GetBoolArg("-listen", DEFAULT_LISTEN);
    fDiscover = args.GetBoolArg("-discover", true);
    const bool ignores_incoming_txs{args.GetBoolArg("-blocksonly", DEFAULT_BLOCKSONLY)};
    assert(!node.addrman);
    node.addrman = std::make_unique<CAddrMan>();
    assert(!node.banman);
    node.banman = std::make_unique<BanMan>(GetDataDir() / "banlist.dat", &uiInterface, args.GetArg("-bantime", DEFAULT_MISBEHAVING_BANTIME));