resources/layouts/_default/redirect.html.twig

<!DOCTYPE html>
<html>
  <head lang="{{ site.language }}">
    <meta charset="utf-8">
    <title>{% trans %}Redirecting…{% endtrans %}</title>
    <link rel="canonical" href="{{ url(page.redirect, {canonical: true}) }}" />
    <meta name="robots" content="noindex" />
    <meta http-equiv="content-type" content="text/html; charset=utf-8" />
    <meta http-equiv="refresh" content="0;url={{ url(page.redirect, {canonical: true}) }}" />
    <script>
      window.location.assign("{{ url(page.redirect, {canonical: true}) }}");
    </script>
  </head>
  <body>
    <h1>{% trans %}Redirecting…{% endtrans %}</h1>
    <a href="{{ url(page.redirect) }}">{% trans %}Click here if you are not redirected.{% endtrans %}</a>
  </body>
</html>