* @param string $cat The category of the configuration value
* @param string $key The configuration key to query
* @param mixed $default_value optional, The value to return if key is not set (default: null)
* @param string $cat The category of the configuration value
* @param string $key The configuration key to query
* @param mixed $default_value optional, The value to return if key is not set (default: null)