core-bundle/src/Resources/contao/pages/PageError403.php
public function generate($objRootPage=null)
	{
		/** @var PageModel $objPage */
		global $objPage;

		$obj403 = $this->prepare($objRootPage);
		$objPage = $obj403->loadDetails();

		/** @var PageRegular $objHandler */
		$objHandler = new $GLOBALS['TL_PTY']['regular']();

		header('HTTP/1.1 403 Forbidden');
		$objHandler->generate($objPage);
	}
public function generate($objRootPage=null)
	{
		/** @var PageModel $objPage */
		global $objPage;

		$obj403 = $this->prepare($objRootPage);
		$objPage = $obj403->loadDetails();

		/** @var PageRegular $objHandler */
		$objHandler = new $GLOBALS['TL_PTY']['regular']();

		header('HTTP/1.1 403 Forbidden');
		$objHandler->generate($objPage);
	}
Generate an error 403 page

@param PageModel|integer $objRootPage