Mail.php

<?php

declare (strict_types=1);
namespace Drupal\Core\Mail\Attribute;

use Drupal\Component\Plugin\Attribute\Plugin;
use Drupal\Core\StringTranslation\TranslatableMarkup;

/**
 * Defines a Mail attribute for plugin discovery.
 *
 * Plugin Namespace: Plugin\Mail
 *
 * For a working example, see \Drupal\Core\Mail\Plugin\Mail\PhpMail
 *
 * @see \Drupal\Core\Mail\MailInterface
 * @see \Drupal\Core\Mail\MailManager
 * @see plugin_api
 */
class Mail extends Plugin {
    
    /**
     * Constructs a Mail attribute.
     *
     * @param string $id
     *   The plugin ID.
     * @param \Drupal\Core\StringTranslation\TranslatableMarkup $label
     *   The label of the plugin.
     * @param \Drupal\Core\StringTranslation\TranslatableMarkup|null $description
     *   (optional) A description of the plugin.
     * @param class-string|null $deriver
     *   (optional) The deriver class.
     */
    public function __construct(string $id, TranslatableMarkup $label, ?TranslatableMarkup $description = NULL, ?string $deriver = NULL) {
    }

}