$router->addRoute('/login', 'LoginController@index');
$router->addRoute('/user/{id}', 'UserController@show');In this example, the `addRoute` method is used to map the URL path `/user/{id}` to the `show` method of the `UserController`. The `id` parameter can be accessed in the controller action using the `$request->getParam('id')` method. The `addRoute` method is often used in conjunction with other methods in a PHP Router package, such as `get`, `post`, `put`, and `delete`. These methods are used to define routes for each HTTP verb. It is difficult to determine the specific package library from just these code examples, as there are many PHP Router packages available. However, popular PHP Router packages include Slim, Laravel, and Symfony.