ed field.
    - `is_required` - If the panel contains a required field.
    - `children` - The panel’s contents.
    - `header_controls` - Additional panel buttons to display in the header area.
    - `attrs` - Additional HTML attributes to render on the panel.

    When making changes to this template, please ensure that the JavaScript-equivalent `CollapsiblePanel` component is also updated accordingly.

{% endcomment %}
{% fragment as prefix %}{% if id_prefix %}{{ id_prefix }}-{% endif %}{{ id }}{% endf