bulma/docs/_includes/elements/tw-button.html

<a class="bd-tw-button button"
  data-social-network="Twitter"
  data-social-action="tweet"
  data-social-target="{{ site.url }}"
  target="_blank"
  href="https://twitter.com/intent/tweet?text={{ site.title | urlencode }}&hashtags=bulmaio&url={{ site.url }}&via=jgthms">
  <span class="icon">
    <i class="fa fa-twitter"></i>
  </span>
  <span>
    {{ include.label }}
  </span>
</a>