code: private function acceptLicense(): Response
      {
          $request = $this->container->get('request_stack')->getCurrentRequest();
  
          if (null === $request) {
              throw new \RuntimeException('The request stack did not contain a request');
          }
  
          if ('tl_license' !== $request->request->get('FORM_SUBMIT')) {
              return $this->render('license.html.twig');
          }
  
          $this->container->get('contao.install_tool')->persistConfig('licenseAccepted', true);
  
          return $this->getRedirectResponse();
      }
docs: Renders a form to accept the license.
  
  @throws \RuntimeException
  
  @return Response|RedirectResponse