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

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

{% block breadcrumbs %}
  {{ block.super }}
  <li class="breadcrumb-item"><a href="{% url 'ipam:aggregate_list' %}?rir_id={{ object.rir.pk }}">{{ object.rir }}</a></li>
{% endblock %}