PSR-0 is brought up a bit out of the blue here. Let's tie its explanation to the StandardAutoloader:

> The `Zend\Loader\StandardAutoloader` uses a PHP community driven standard called [`PSR-0`](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-0.md). Amongst other things, this standard defines a way for PHP to map class names to the file system. So with this configured, the application knows that our `Album\Controller\ListController` class should exist at `/module/Album/src/Album/Controller/ListController.php`.