docs/_templates/sourcelink.html

{%- if show_source and has_source and sourcename %}
  <div class="sourcelink">
  {%- if edit_on_github_url %}
    <a href="{{ edit_on_github_url }}" class="icon icon-github"
           rel="nofollow"> {{ _('Edit on GitHub') }}</a>
  {%- endif %}
</div>
{%- endif %}