cupper-hugo-theme/layouts/shortcodes/warning.html

<aside aria-label="warning" class="note warning">
  <div>
    <svg class="sign" aria-hidden="true" viewBox="0 0 48.430474 41.646302" focusable="false">
      <use href="#warning"></use>
    </svg>
    {{ .Inner | markdownify }}
  </div>
</aside>