improvements-2.x-dev/modules/improvements_contact/src/Plugin/Menu/LocalTask/ContactFormMessagesLocalTask.php

<?php

namespace Drupal\improvements_contact\Plugin\Menu\LocalTask;

use Drupal\Core\Menu\LocalTaskDefault;
use Drupal\Core\Routing\RouteMatchInterface;

class ContactFormMessagesLocalTask extends LocalTaskDefault {

  /**
   * {@inheritDoc}
   */
  public function getOptions(RouteMatchInterface $route_match): array {
    $options = parent::getOptions($route_match);
    $options['query']['form'] = \Drupal::routeMatch()->getRawParameter('contact_form');
    return $options;
  }

}