Node Edit Form - Sidebar (via custom Seven sub theme)

details.twig

{#
/**
 * @file
 * Component template for details element.
 * https://www.drupal.org/project/components
 *
 * Variables:
 * - summary: HTML/text to display in <summary> element
 * - details: Main content of details.
 * - open: If the details element should be open by default.
 */
#}
{% set open = open ? ' open' : '' %}
<details class="js-form-wrapper form-wrapper"{{ open }}>
  {% if summary %}
    {% block summary %}
      <summary>{{ summary }}</summary>
    {% endblock %}
  {% endif %}
  <div class="details-wrapper">
    {% block details %}
      {{ details }}
    {% endblock %}
  </div>
</details>

entity-form.twig

{#
/**
 * @file
 * Component template for Entity forms.
 * https://www.drupal.org/project/components
 *
 * @see seven_sub_form_alter()
 */
#}

{{ attach_library('seven/node-form') }}
{% block wrapper %}
  <div class="layout-node-form clearfix">
    <div class="layout-region layout-region-node-main">
      {% block main %}
        {{ form|without('actions') }}
      {% endblock %}
    </div>
    <div class="layout-region layout-region-node-secondary">
      {% block sidebar %}
        <div class="entity-meta form-wrapper">
          {% block entity_meta_header %}
            <div class="entity-meta__header">
              {% block entity_meta_header_content %}{% endblock %}
          </div>
          {% endblock %}
          {% block entity_meta_content %}{% endblock %}
        </div>
      {% endblock %}
    </div>
    <div class="layout-region layout-region-node-footer">
      {% block footer %}
        {{ form.actions }}
      {% endblock %}
    </div>
    {{ children }}
  </div>
{% endblock %}

media-form.html.twig

{#
/**
 * @file
 * Theme override for a media edit form.
 */
#}
{% embed '@seven-components/entity-form.twig' %}

  {% block main %}
    {{ form|without(
      'actions',
      'author',
      'field_tags',
      'revision_information',
      'xmlsitemap',
      'field_distribution_partner'
      )
    }}
  {% endblock %}

  {% block entity_meta_header_content %}
    {{ form.revision_information['revision'] }}
    {{ form.revision_information['revision_log'] }}
  {% endblock %}

  {% block entity_meta_content %}
   {% if form.field_tags|render %}
      {% embed '@seven-components/details.twig' with { summary: 'Metadata'|t, open: true } %}
        {% block details %}
          {{ form.field_tags }}
          {{ form.field_distribution_partner }}
        {% endblock %}
      {% endembed %}
    {% endif %}
   {{ form.author }}
   {{ form.xmlsitemap }}
  {% endblock %}

{% endembed %}

node-edit-form.html.twig

{#
/**
 * @file
 * Theme override for a node edit form.
 */
#}
{% embed '@seven-components/entity-form.twig' %}
  {% block main %}
    {{ form|without(
      'actions',
      'advanced',
      'author',
      'field_editorial_type',
      'field_kicker',
      'field_publish_date_display',
      'group_article_information',
      'menu',
      'meta',
      'path_settings',
      'publish_date',
      'revision',
      'xmlsitemap'
      )
    }}
  {% endblock %}

  {# This is the sidebar stuff, from here down. #}
  {% block entity_meta_header_content %}
    {{ form.meta['published'] }}
    {{ form.meta['author'] }}
    {{ form.meta['moderation_state'] }}
    {{ form.meta['changed'] }}
    {{ form.meta['revision_information'] }}
    {{ form.meta|without(
      'author',
      'changed',
      'moderation_state',
      'published',
      'revision_information'
    ) }}
  {% endblock %}

  {% block entity_meta_content %}
    {{ form.group_article_information }}
    {% if form.field_editorial_type|render or form.field_kicker|render %}
      {% embed '@seven-components/details.twig' with { summary: 'Integrations'|t } %}
        {% block details %}
          {{ form.field_editorial_type }}
          {{ form.field_kicker }}
        {% endblock %}
      {% endembed %}
    {% endif %}
    {{ form.author }}
    {{ form.path_settings }}
    {{ form.menu }}
    {{ form.xmlsitemap }}
  {% endblock %}

{% endembed %}

seven-sub.info.yml

# Needs Component module
# https://www.drupal.org/project/components
  
component-libraries:
  seven-components:
    paths:
      - components

seven_sub.theme.php

<?php
{#
/**
 * @file
 * seven_sub.theme
 */
#}
  
use Drupal\Core\Render\Element;

/**
 * Implements hook_form_alter().
 */
function seven_sub_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  // Remove the "advanced" group in the above base forms, which cover all
  // variants of node, taxonomy and media entity forms.
  $base_ids = ['media_form', 'media_edit_form', 'taxonomy_term_form', 'taxonomy_edit_form', 'node_form', 'node_edit_form'];
  if (!empty($form_state->getBuildInfo()['base_form_id'])) {
    if (in_array($form_state->getBuildInfo()['base_form_id'], $base_ids)) {
      foreach (Element::children($form) as $key) {
        if (!empty($form[$key]['#group']) && $form[$key]['#group'] == 'advanced') {
          unset($form[$key]['#group']);
        }
      }
    }
  }
}

/**
 * Implements hook_theme().
 */
function seven_sub_theme($existing, $type, $theme, $path) {
  return array(
    'media_form' => array(
      'template' => 'form/media-form',
      'render element' => 'form',
    ),
    'taxonomy_term_form' => array(
      'template' => 'form/taxonomy-term-form',
      'render element' => 'form',
    ),
  );
}

taxonomy-term-form.html.twig

{#
/**
 * @file
 * Theme override for a taxonomy edit form.
 */
#}
{% embed '@seven-components/entity-form.twig' %}

  {% block main %}
    {{ form|without(
      'actions',
      'author',
      'field_tags',
      'path',
      'relations',
      'xmlsitemap'
      )
    }}
  {% endblock %}

  {% block entity_meta_header %}{% endblock %}

  {% block entity_meta_content %}
   {% if form.field_tags|render %}
      {% embed '@seven-components/details.twig' with { summary: 'Metadata'|t, open: true } %}
        {% block details %}
          {{ form.field_tags }}
        {% endblock %}
      {% endembed %}
    {% endif %}
   {{ form.author }}
   {% if form.path|render %}
      {% embed '@seven-components/details.twig' with { summary: 'URL Path Settings'|t } %}
        {% block details %}
          {{ form.path }}
        {% endblock %}
      {% endembed %}
   {% endif %}
   {{ form.relations }}
   {{ form.xmlsitemap }}
  {% endblock %}

{% endembed %}