Strange, I checked the code and the only thing it does is checking if the file exists and is writable. Little code snippit from ./setup/index.php:
elseif(!file_exists(CONFIGFILE) || !is_writable(CONFIGFILE)) { //writable config file??
$errors='Configuration file is not writable';
$inc='chmod.inc.php';
}
So it's only using existing PHP functions.
-rwxrwxrwx is correct, that's the same with me.