maintenance-1.0.0-beta1/js/maintenance-reload.js

((Drupal, once) => {
  Drupal.behaviors.maintenanceReloadButton = {
    attach(context) {
      once('maintenanceReload', '[data-maintenance-reload]', context).forEach((button) => {
        button.addEventListener('click', (e) => {
          e.preventDefault();
          location.reload();
        });
      });
    }
  };
})(Drupal, once);