{#
/**
 * @file
 * Theme implementation to display an insert_box node.
 *
 * @see template_preprocess_node()
 * @see sw_preprocess_node_insert_box()
 *
 * @ingroup themeable
 */
#}
{%
  set classes = [
    'node--type-insert-box',
    not node.isPublished() ? 'node--unpublished',
  ]
%}
<article{{ attributes.addClass(classes) }}>

  {{ title_prefix }}
    <h2{{ title_attributes }}>{{ label }}</h2>
  {{ title_suffix }}
  <div{{ content_attributes }}>
    {{ content }}
  </div>

</article>

Add our own twig template for insert boxes:
Theme: Add our own twig template for insert boxes:

- We don't want core's behavior where {{ label }} ever becomes a link.
- We always want to render {{ label }} as an <h2>, even on full page
  views, so that admins see the insert box as it will actually appear.
