joomla-oauth-server/plg_system_oauthserver/services/provider.php

<?php

use Joomla\DI\ServiceProviderInterface;

\defined('_JEXEC') or die;

return new class implements ServiceProviderInterface {

    public function register(\Joomla\DI\Container $container)
    {
        // TODO: Implement register() method.
    }
};