core-bundle/src/Resources/contao/elements/ContentElement.php
public function generate()
	{
		if (TL_MODE == 'FE' && !BE_USER_LOGGED_IN && ($this->invisible || ($this->start != '' && $this->start > time()) || ($this->stop != '' && $this->stop < time())))
		{
			return '';
		}

		$this->Template = new FrontendTemplate($this->strTemplate);
		$this->Template->setData($this->arrData);

		$this->compile();

		// Do not change this order (see #6191)
		$this->Template->style = !empty($this->arrStyle) ? implode(' ', $this->arrStyle) : '';
		$this->Template->class = trim('ce_' . $this->type . ' ' . $this->cssID[1]);
		$this->Template->cssID = !empty($this->cssID[0]) ? ' id="' . $this->cssID[0] . '"' : '';

		$this->Template->inColumn = $this->strColumn;

		if ($this->Template->headline == '')
		{
			$this->Template->headline = $this->headline;
		}

		if ($this->Template->hl == '')
		{
			$this->Template->hl = $this->hl;
		}

		if (!empty($this->objModel->classes) && \is_array($this->objModel->classes))
		{
			$this->Template->class .= ' ' . implode(' ', $this->objModel->classes);
		}

		// Tag the response
		if (System::getContainer()->has('fos_http_cache.http.symfony_response_tagger'))
		{
			/** @var ResponseTagger $responseTagger */
			$responseTagger = System::getContainer()->get('fos_http_cache.http.symfony_response_tagger');
			$responseTagger->addTags(array('contao.db.tl_content.' . $this->id));
		}

		return $this->Template->parse();
	}
public function generate()
	{
		if (TL_MODE == 'FE' && !BE_USER_LOGGED_IN && ($this->invisible || ($this->start != '' && $this->start > time()) || ($this->stop != '' && $this->stop < time())))
		{
			return '';
		}

		$this->Template = new FrontendTemplate($this->strTemplate);
		$this->Template->setData($this->arrData);

		$this->compile();

		// Do not change this order (see #6191)
		$this->Template->style = !empty($this->arrStyle) ? implode(' ', $this->arrStyle) : '';
		$this->Template->class = trim('ce_' . $this->type . ' ' . $this->cssID[1]);
		$this->Template->cssID = !empty($this->cssID[0]) ? ' id="' . $this->cssID[0] . '"' : '';

		$this->Template->inColumn = $this->strColumn;

		if ($this->Template->headline == '')
		{
			$this->Template->headline = $this->headline;
		}

		if ($this->Template->hl == '')
		{
			$this->Template->hl = $this->hl;
		}

		if (!empty($this->objModel->classes) && \is_array($this->objModel->classes))
		{
			$this->Template->class .= ' ' . implode(' ', $this->objModel->classes);
		}

		// Tag the response
		if (System::getContainer()->has('fos_http_cache.http.symfony_response_tagger'))
		{
			/** @var ResponseTagger $responseTagger */
			$responseTagger = System::getContainer()->get('fos_http_cache.http.symfony_response_tagger');
			$responseTagger->addTags(array('contao.db.tl_content.' . $this->id));
		}

		return $this->Template->parse();
	}
Parse the template

@return string