ViewFormBase::isDefaultDisplayShown

public ViewFormBase::isDefaultDisplayShown(ViewUI $view)

public function isDefaultDisplayShown(ViewUI $view) {
  // Always show the default display for advanced users who prefer that mode.
  $advanced_mode = \Drupal::config('views.settings')->get('ui.show.master_display');
  // For other users, show the default display only if there are no others, and
  // hide it if there's at least one "real" display.
  $additional_displays = (count($view->getExecutable()->displayHandlers) == 1);

  return $advanced_mode || $additional_displays;
}