netbox/netbox/templates/dcim/inc/rack_elevation.html

{% load helpers %}

<ul class="rack_legend">
    {% for u in rack.units %}
        <li>{{ u }}</li>
    {% endfor %}
</ul>

<div class="rack_frame">

  <img src="{% url 'dcim-api:rack-elevation-detail' pk=rack.pk %}" height="100%">

</div>