Products may be accessed using SEO friendly URLs like /my-product instead of /catalog/product/view/id/{ID}How is this...

An event observer adds RewriteRules to .htaccess on product save

Magento\Catalog\Controller\Product\View::loadByUrlKey loads product pages using the url_key attribute value

Using a URL Rewrite stored in the database connecting the request path with the target path

A plugin on \Magento\UrlRewrite\Controller\Router::match loads products by the url_key attribute