Markup: components/pagination/pagination.twig
<nav class="pager" role="navigation" aria-labelledby="pagination-heading">
  <h4 id="pagination-heading" class="visuallyhidden">Pagination</h4>
  <ul class="pager__items">
    <li class="pager__item is-active">
      <a href="#">
          <span class="visuallyhidden">
           Current Page
          </span>1</a>
      </li>
    <li class="pager__item">
      <a href="#">
        <span class="visuallyhidden">
          Page
        </span>2</a>
    </li>
    <li class="pager__item">
      <a href="" title="Current page">
        <span class="visuallyhidden">
          Page
        </span>3</a>
    </li>
    <li class="pager__item pager__item--next">
      <a href="#" title="Go to next page" rel="next">
        <span class="visuallyhidden">Next page</span>
        <span aria-hidden="true">››</span>
      </a>
    </li>
  </ul>
</nav>
Source: _sr18-styleguide.scss, line 371