On my Linux Mint 19.1:
```bash
$ umask
0022
```

After the first run of `bitcoin-qt -sysperm=false` the `0700` permissions are expected for both the datadir (`~/.bitcoin`) and the walletdir (`~/.bitcoin/wallets`).

Actually, the directories are created with such access permissions:
```bash
$ stat ~/.bitcoin | grep Uid
Access: (0755/drwxr-xr-x)  Uid: ( 1000/ hebasto)   Gid: ( 1000/ hebasto)
$ stat ~/.bitcoin/wallets | grep Uid
Access: (0755/drwxr-xr-x)  Uid: ( 1000/ hebasto)   Gid: ( 1000/ hebasto)
```

Refs:
- #4286
- #13371
- #13389

NOTE: reading through the initial PR #4286 makes me think it was controversial. Is it a better and simpler way to just get rid of `-sysperm` option? I believe a user who needs this option can easily run `chown` command.
connOptions.m_i2p_accept_incoming = args.GetBoolArg("-i2pacceptincoming", DEFAULT_I2P_ACCEPT_INCOMING);
    if (!node.connman->Start(*node.scheduler, connOptions)) {
        return false;
    }
     ********************************************************* Step 13: finished
     At this point, the RPC is "started", but still in warmup, which means it
     cannot yet be called. Before we make it callable, we need to make sure
     that the RPC's view of the best block is valid and consistent with
     ChainstateManager's active tip.
    
     If we do not do this, RPC's view of the best block will be height=0 and
     hash=0x0. This will lead to erroroneous responses for things like
     waitforblockheight.
    RPCNotifyBlockChange(WITH_LOCK(chainman.GetMutex(), return chainman.ActiveTip()));
    SetRPCWarmupFinished();
    uiInterface.InitMessage(_("Done loading").translated);
    for (const auto& client : node.chain_clients) {
        client->start(*node.scheduler);
    }
    BanMan* banman = node.banman.get();
    node.scheduler->scheduleEvery([banman]{
        banman->DumpBanlist();
    }, DUMP_BANS_INTERVAL);
    if (node.peerman) node.peerman->StartScheduledTasks(*node.scheduler);
#if HAVE_SYSTEM
    StartupNotify(args);
#endif
    return true;
}