codeninjasuk.github.io/_includes/comments-providers/utterances.html

<script>
  'use strict';

  (function() {
    var commentContainer = document.querySelector('#utterances-comments');

    if (!commentContainer) {
      return;
    }

    var script = document.createElement('script');
    script.setAttribute('src', 'https://utteranc.es/client.js');
    script.setAttribute('repo', '{{ site.repository }}');
    script.setAttribute('issue-term', '{{ site.comments.utterances.issue_term | default: "pathname" }}');
    {% if site.comments.utterances.label %}script.setAttribute('label', '{{ site.comments.utterances.label }}');{% endif %}
    script.setAttribute('theme', '{{ site.comments.utterances.theme | default: "github-light" }}');
    script.setAttribute('crossorigin', 'anonymous');

    commentContainer.appendChild(script);
  })();
</script>