{%-
        assign files =
          site.static_files
          | where_exp: "file", "file.extname contains '.htm'"
    -%}

    {%- if files.size > 0 %}    <ul>
      {%- for file in files -%}
        {%-
            assign path =
              file.path
              | remove_first: page.url
              | remove_first: "/index.html"
        %}
      <li>
        <a href="{{- path | append: "/" -}}">{{- path -}}</a>
      </li>
      {%- endfor %}
    </ul>
    {%- endif %}