netbox-community-netbox/netbox/templates/ipam/prefix/base.html

{% extends 'generic/object.html' %}
{% load buttons %}
{% load helpers %}

{% block breadcrumbs %}
  {{ block.super }}
  {% if object.vrf %}
    <li class="breadcrumb-item"><a href="{% url 'ipam:prefix_list' %}?vrf_id={{ object.vrf.pk }}">{{ object.vrf }}</a></li>
  {% endif %}
{% endblock %}