core-bundle/src/Resources/contao/dca/tl_page.php
public function showFallbackWarning()
	{
		if (Contao\Input::get('act') != '')
		{
			return;
		}

		$messages = new Contao\Messages();
		Contao\Message::addRaw($messages->languageFallback());
	}
public function showFallbackWarning()
	{
		if (Contao\Input::get('act') != '')
		{
			return;
		}

		$messages = new Contao\Messages();
		Contao\Message::addRaw($messages->languageFallback());
	}
Show a warning if there is no language fallback page