Backend\Core\Engine\TwigTemplate::getContent PHP Method

    public function getContent($template)
    {
        $this->parseConstants();
        $this->parseAuthentication();
        $this->parseAuthenticatedUser();
        $this->parseDebug();
        $this->parseLabels();
        $this->parseLocale();
        $this->parseVars();
        $template = str_replace(BACKEND_MODULES_PATH, '', $template);
        // path to TwigBridge library so we can locate the form theme files.
        $appVariableReflection = new ReflectionClass(AppVariable::class);
        $vendorTwigBridgeDir = dirname($appVariableReflection->getFileName());
        // render the compiled File
        $loader = new Twig_Loader_Filesystem(array(BACKEND_MODULES_PATH, BACKEND_CORE_PATH, $vendorTwigBridgeDir . '/Resources/views/Form'));
        $twig = new Twig_Environment($loader, array('cache' => Model::getContainer()->getParameter('kernel.cache_dir') . '/twig', 'debug' => $this->debugMode));
        // connect symphony forms
        $formEngine = new TwigRendererEngine(array('Layout/Templates/FormLayout.html.twig'));
        $formEngine->setEnvironment($twig);
        $twig->addExtension(new SymfonyFormExtension(new TwigRenderer($formEngine, Model::get('security.csrf.token_manager'))));
        $twigTranslationExtensionClass = Model::getContainer()->getParameter('twig.extension.trans.class');
        $twig->addExtension(new $twigTranslationExtensionClass(Model::get('translator')));
        // debug options
        if ($this->debugMode === true) {
            $twig->addExtension(new Twig_Extension_Debug());
        }
        if (count($this->forms) > 0) {
            foreach ($this->forms as $form) {
                $twig->addGlobal('form_' . $form->getName(), $form);
            }
        }
        // should always be included, makes it possible to parse SpoonForm in twig
        new FormExtension($twig);
        // start the filters / globals
        TwigFilters::getFilters($twig, 'Backend');
        $this->startGlobals($twig);
        return $twig->render($template, $this->variables);
    }

 /**
  * Display, this wil output the template to the browser
  * If no template is specified we build the path form the current module and action
  *
  * @param string $template The template to use, if not provided it will be based on the action.
  */
 public function display($template = null)
 {
     // parse header
     $this->header->parse();
     /*
      * If no template is specified, we have to build the path ourself. The default template is
      * based on the name of the current action
      */
     if ($template === null) {
         $template = '/' . $this->getModule() . '/Layout/Templates/' . $this->URL->getAction() . '.html.twig';
     }
     $this->content = $this->tpl->getContent($template);
 }