mirror-crappy-reverie/_includes/analytics_head.html

{% if site.google_analytics_ga4 %}
      <script async src="https://www.googletagmanager.com/gtag/js?id={{ site.google_analytics_ga4 }}"></script>
      <script>
        window.dataLayer = window.dataLayer || [];
        function gtag(){dataLayer.push(arguments);}
        gtag('js', new Date());
        gtag('config', '{{ site.google_analytics_ga4 }}');
      </script>
{% endif %}