Localized Settings Files in Drupal

/** @file settings.php */
/**
* Usually this page contains a switch that manages configuration values for 
* for various environments. These rules are shared between users.
*/
if (file_exists(DRUPAL_ROOT . '/sites/default/settings.env-conf.php')) {
  require_once DRUPAL_ROOT . '/sites/default/settings.env-conf.php';
}

/**
* Database connections info and modification applicable to the user's
* local machine are kept here. 
*/
if (file_exists(DRUPAL_ROOT . '/sites/default/settings.local.php')) {
  require_once DRUPAL_ROOT . '/sites/default/settings.local.php';
}