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.
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)};
    {
        
        std::vector<bool> asmap;
        if (args.IsArgSet("-asmap")) {
            fs::path asmap_path = args.GetPathArg("-asmap", DEFAULT_ASMAP_FILENAME);
            if (!asmap_path.is_absolute()) {
                asmap_path = gArgs.GetDataDirNet()  asmap_path;
            }
            if (!fs::exists(asmap_path)) {
                InitError(strprintf(_("Could not find asmap file %s"), fs::quoted(fs::PathToString(asmap_path))));
                return false;
            }
            asmap = DecodeAsmap(asmap_path);
            if (asmap.size() == 0) {
                InitError(strprintf(_("Could not parse asmap file %s"), fs::quoted(fs::PathToString(asmap_path))));
                return false;