FieldExampleController.php

<?php

namespace Drupal\field_example\Controller;

use Drupal\examples\Utility\DescriptionTemplateTrait;

/**
 * Controller for field example description page.
 *
 * This class uses the DescriptionTemplateTrait to display text we put in the
 * templates/description.html.twig file.
 */
class FieldExampleController {
    use DescriptionTemplateTrait;
    
    /**
     * {@inheritdoc}
     */
    protected function getModuleName() {
        return 'field_example';
    }

}