read-more.twig

<a{{ attributes.addClass('read-more').setAttribute('href', url) }}>
  {% block text %}{% endblock %}
  <span class="visually-hidden">
    - {% block a11y %}{% endblock %}
  </span>
  <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 600 600" class="read-more__icon">
    <path fill="none" d="M159.19 117.37v365.26L341.82 300 159.19 117.37z"/>
    <path fill="#008068" d="M341.82 300L159.19 482.63v98.99L440.81 300 159.19 18.38v98.99L341.82 300z"/>
  </svg>
</a>

File

core/profiles/demo_umami/themes/umami/components/read-more/read-more.twig

<a{{ attributes.addClass('read-more').setAttribute('href', url) }}>
  {% block text %}{% endblock %}
  <span class="visually-hidden">
    - {% block a11y %}{% endblock %}
  </span>
  <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 600 600" class="read-more__icon">
    <path fill="none" d="M159.19 117.37v365.26L341.82 300 159.19 117.37z"/>
    <path fill="#008068" d="M341.82 300L159.19 482.63v98.99L440.81 300 159.19 18.38v98.99L341.82 300z"/>
  </svg>
</a>