Config Files Are Just PHP Arrays
Open a Symfony project and the routes are in YAML. The services are in YAML. The bundles are in PHP, but only as an array of class names. Open a Laravel project and routing lives in PHP, but services hide behind ServiceProviders that wrap bindings inside register() and boot() methods. Both approaches put a layer between you and the configuration, and that layer is where every typo, missing key, and "where is this interface bound" question accumulates.