netbox/netbox/templates/dcim/device_component.html

{% extends 'generic/object.html' %}
{% load helpers %}
{% load perms %}
{% load custom_links %}
{% load plugins %}

{% block title %}{{ object.device }} / {{ object }}{% endblock %}

{% block breadcrumbs %}
  <li><a href="{% url 'dcim:device_list' %}">Devices</a></li>
  <li><a href="{{ object.device.get_absolute_url }}">{{ object.device }}</a></li>
{% endblock %}