$router->get('/posts/:id', function($id){ // logic for fetching and displaying blog post by ID goes here });In this example, the colon syntax is used to indicate a dynamic parameter in the URL. When a user navigates to a URL like `/posts/123`, PHP Route will automatically extract the value `123` and pass it to the callback function as the parameter `$id`. Package library: PHP Route is distributed as a standalone library, and can be installed via Composer by running `composer require phroute/phroute`.