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.
}
        }
    } else {
        LogPrintf("Setting NODE_NETWORK on non-prune mode\n");
        nLocalServices = ServiceFlags(nLocalServices | NODE_NETWORK);
    }
     ********************************************************* Step 11: import blocks
    if (!CheckDiskSpace(gArgs.GetDataDirNet())) {
        InitError(strprintf(_("Error: Disk space is low for %s"), fs::quoted(fs::PathToString(gArgs.GetDataDirNet()))));
        return false;
    }
    if (!CheckDiskSpace(gArgs.GetBlocksDirPath())) {
        InitError(strprintf(_("Error: Disk space is low for %s"), fs::quoted(fs::PathToString(gArgs.GetBlocksDirPath()))));
        return false;
    }
    int chain_active_height = WITH_LOCK(cs_main, return chainman.ActiveChain().Height());
     On first startup, warn on low block storage space
    if (!fReindex && !fReindexChainState && chain_active_height <= 1) {
        uint64_t additional_bytes_needed{
            chainman.m_blockman.IsPruneMode() ?
                chainman.m_blockman.GetPruneTarget() :
                chainparams.AssumedBlockchainSize() * 1024 * 1024 * 1024};
        if (!CheckDiskSpace(args.GetBlocksDirPath(), additional_bytes_needed)) {
            InitWarning(strprintf(_(
                    "Disk space for %s may not accommodate the block files. " \
                    "Approximately %u GB of data will be stored in this directory."
                ),
                fs::quoted(fs::PathToString(args.GetBlocksDirPath())),
                chainparams.AssumedBlockchainSize()
            ));