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.
on any a
    connOptions.bind_on_any = args.GetArgs("-bind").empty() && args.GetArgs("-whitebind").empty();
     Emit a warning if a bad port is given to -port= but only if -bind and -whitebind are not
     given, because if they are, then -port= is ignored.
    if (connOptions.bind_on_any && args.IsArgSet("-port")) {
        const uint16_t port_arg = args.GetIntArg("-port", 0);
        if (IsBadPort(port_arg)) {
            InitWarning(BadPortWarning("-port", port_arg));
        }
    }
    CService onion_service_target;
    if (!connOptions.onion_binds.empty()) {
        onion_service_target = connOptions.onion_binds.front();
    } else {
        onion_service_target = DefaultOnionServiceTarget();
        connOptions.onion_binds.push_back(onion_service_target);
    }
    if (args.GetBoolArg("-listenonion", DEFAULT_LISTEN_ONION)) {
        if (connOptions.onion_binds.size() > 1) {
            InitWarning(strprintf(_("More than one onion bind address is provided. Using %s "
                                    "for the automatically created Tor onion service."),
                                  onion_service_target.ToStringIPPort()));
        }
        StartTorControl(onion_service_target);
    }
    if (connOptions.bind_on_any) {
         Only 
         any a
        Discover();
    }