website/_includes/tree.html

{% for item in include.tree %}
  {% if item.section %}
    <div class="item" data-title="{{ item.title }}">
      <div class="container">
        {% include_cached tree.html tree=item.section %}
      </div>
    </div>
  {% else %}

    {% capture whitespace %}
      {% if item.path %}
        {% assign path   = item.path %}
        {% assign title  = item.title %}
        {% assign target = " target='_blank'" %}
      {% else %}
        {% assign page  = site.pages | where: "path", item | first %}
        {% assign title = page.title %}
        {% assign path  = page.url %}
      {% endif %}
    {% endcapture %}

    {% if path %}
      <a class="item" data-title="{{ title }}" href="{{ path }}"{{ target }}></a>
    {% endif %}
  {% endif %}
{% endfor %}