netbox/netbox/utilities/templates/navigation/nav_items.html

<div id="sidenav-accordion" class="accordion accordion-flush nav-item">
  {% for menu in nav_items %}

    {# Main Collapsible Menu #}
    <div class="accordion-item">
      <a
        href="#"
        role="button"
        aria-expanded="true"
        data-bs-toggle="collapse"
        data-bs-target="#{{ menu.label|lower }}"
        class="d-flex justify-content-between align-items-center accordion-button nav-link collapsed">
          <span class="fw-bold sidebar-nav-link">
            <i class="mdi mdi-{{ menu.icon }} me-1"></i>
            {{ menu.label }}
          </span>
        </a>

      <div id="{{ menu.label|lower }}" class="accordion-collapse collapse" data-bs-parent="#sidenav-accordion">
        <div class="multi-level accordion-body px-0">
          
          {% for group in menu.groups %}
            {# Within each main menu, there are groups of menu items #}
            <div class="flex-column nav px-2">
              
              {% if menu.groups|length > 1 %}
                <h6 class="accordion-item-title">{{ group.label }}</h6>
              {% endif %}
              
              {% for item in group.items %}
                {# Each Menu Item #}
                <div class="nav-item d-flex justify-content-between align-items-center">
                  
                  {# Menu Link with Text #}
                  <a class="nav-link flex-grow-1 me-1" href="{% url item.url %}">
                    {{ item.label }}
                  </a>
                  
                  {# Add & Import Buttons #}
                  <div class="btn-group">
                    {% if item.has_add %}
                        <a class="btn btn-sm btn-success lh-1" href="{% url item.add_url %}" title="Add {{ item.label }}">
                          <i class="mdi mdi-plus-thick"></i>
                        </a>
                    {% endif %}
                    {% if item.has_import %}
                        <a class="btn btn-sm btn-outline-success lh-1" href="{% url item.import_url %}" title="Import {{ item.label }}">
                          <i class="mdi mdi-upload"></i>
                        </a>
                    {% endif %}
                  </div>

                </div>
              {% endfor %}

            </div>

            {# Show a divider if not the last group #}
            {% if forloop.counter != menu.groups|length %}
              <hr class="dropdown-divider my-2" />
            {% endif %}

          {% endfor %}

        </div>
      </div>
    </div>
  {% endfor %}
</div>