ansible/docs/docsite/_themes/sphinx_rtd_theme/ansible_versions.html

<!--- Based on https://github.com/rtfd/sphinx_rtd_theme/pull/438/files -->
{# Creates dropdown version selection in the top-left navigation. #}
<div class="version">
  {% if (not READTHEDOCS) and (available_versions is defined) %}
    <div class="version-dropdown">
      <select class="version-list" id="version-list" onchange="javascript:location.href = this.value;">
        <script> x = document.getElementById("version-list"); </script>
        {% for slug in available_versions %}
          <script>
            current_url = window.location.href;
            option = document.createElement("option");
            option.text = "{{ slug }}";
            if ( "{{ slug }}" == "{{ current_version }}" ) {
              option.selected = true;
            }
            if (current_url.search("{{ current_version }}") > -1) {
              option.value = current_url.replace("{{ current_version }}","{{ slug }}");
            } else {
              option.value = current_url.replace("latest","{{ slug }}");
            }
            x.add(option);
          </script>
        {% endfor %}
      </select>
    </div>
  {% else %}
    {{ nav_version }}
  {% endif %}
</div>