MenuTest.php

<?php

declare (strict_types=1);
namespace Drupal\migrate_drupal_message_test\Plugin\migrate\source;

use Drupal\system\Plugin\migrate\source\Menu;

/**
 * Source plugin with a source id removed from the array returned by fields().
 *
 * @MigrateSource(
 *   id = "d7_menu_test",
 *   source_module = "menu"
 * )
 */
class MenuTest extends Menu {
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        $fields = parent::fields();
        unset($fields['menu_name']);
        return $fields;
    }

}