protected function addAdditionalHeaderData()
    {
        /** @var PageRenderer $pageRenderer */
        $pageRenderer = GeneralUtility::makeInstance(PageRenderer::class);
        $pageRenderer->loadJquery();
        $publicResourcesPath = $this->extensionPath . 'Resources/Public/';
        $pageRenderer->addJsFile($publicResourcesPath . 'JavaScript/BackEnd.js', 'text/javascript', false);
        $pageRenderer->addCssFile($publicResourcesPath . 'CSS/BackEnd.css', 'stylesheet', 'all', '', false);
    }