task: #3582018 Remove or move the uses of classy templates in default admin theme

WHAT IS THIS DIRECTORY FOR?

--------------------------------

This directory is for templates previously inherited from the Classy theme.

WHY WERE CLASSY TEMPLATES COPIED HERE?

-------------------------------------------

Classy was removed in Drupal 10. To prepare for Classy's removal, templates that

would otherwise be inherited from Classy are copied here.

{#

/**

 * @file

 * Theme override for the search form block.

 *

 * Available variables:

 * - plugin_id: The ID of the block implementation.

 * - label: The configured label of the block if visible.

 * - configuration: A list of the block's configuration values, including:

 *   - label: The configured label for the block.

 *   - label_display: The display settings for the label.

 *   - provider: The module or other provider that provided this block plugin.

 *   - Block plugin specific settings will also be stored here.

 * - in_preview: Whether the plugin is being rendered in preview mode.

 * - content: The content of this block.

 * - attributes: A list HTML attributes populated by modules, intended to

 *   be added to the main container tag of this template. Includes:

 *   - id: A valid HTML ID and guaranteed unique.

 * - title_attributes: Same as attributes, except applied to the main title

 *   tag that appears in the template.

 * - title_prefix: Additional output populated by modules, intended to be

 *   displayed in front of the main title tag that appears in the template.

 * - title_suffix: Additional output populated by modules, intended to be

 *   displayed after the main title tag that appears in the template.

 *

 * @see template_preprocess_block()

 * @see search_preprocess_block()

 */

#}

{%

  set classes = [

    'block',

    'block-search',

    'container-inline',

  ]

%}

<div{{ attributes.addClass(classes) }}>

  {{ title_prefix }}

  {% if label %}

    <h2{{ title_attributes }}>{{ label }}</h2>

  {% endif %}

  {{ title_suffix }}

  {% block content %}

    {{ content }}

  {% endblock %}

</div>

{% extends "block.html.twig" %}

{#

/**

 * @file

 * Theme override for a branding block.

 *

 * Each branding element variable (logo, name, slogan) is only available if

 * enabled in the block configuration.

 *

 * Available variables:

 * - site_logo: Logo for site as defined in Appearance or theme settings.

 * - site_name: Name for site as defined in Site information settings.

 * - site_slogan: Slogan for site as defined in Site information settings.

 */

#}

{% block content %}

  {% if site_logo %}

    <a href="{{ path('<front>') }}" rel="home" class="site-logo">

      <img src="{{ site_logo }}" alt="{{ 'Home'|t }}" fetchpriority="high" />

    </a>

  {% endif %}

  {% if site_name %}

    <div class="site-name">

      <a href="{{ path('<front>') }}" rel="home">{{ site_name }}</a>

    </div>

  {% endif %}

  {% if site_slogan %}

    <div class="site-slogan">{{ site_slogan }}</div>

  {% endif %}

{% endblock %}

{#

/**

 * @file

 * Theme override for a menu block.

 *

 * Available variables:

 * - plugin_id: The ID of the block implementation.

 * - label: The configured label of the block if visible.

 * - configuration: A list of the block's configuration values.

 *   - label: The configured label for the block.

 *   - label_display: The display settings for the label.

 *   - provider: The module or other provider that provided this block plugin.

 *   - Block plugin specific settings will also be stored here.

 * - in_preview: Whether the plugin is being rendered in preview mode.

 * - content: The content of this block.

 * - attributes: HTML attributes for the containing element.

 *   - id: A valid HTML ID and guaranteed unique.

 * - title_attributes: HTML attributes for the title element.

 * - content_attributes: HTML attributes for the content element.

 * - title_prefix: Additional output populated by modules, intended to be

 *   displayed in front of the main title tag that appears in the template.

 * - title_suffix: Additional output populated by modules, intended to be

 *   displayed after the main title tag that appears in the template.

 *

 * Headings should be used on navigation menus that consistently appear on

 * multiple pages. When this menu block's label is configured to not be

 * displayed, it is automatically made invisible using the 'visually-hidden' CSS

 * class, which still keeps it visible for screen-readers and assistive

 * technology. Headings allow screen-reader and keyboard only users to navigate

 * to or skip the links.

 * See http://juicystudio.com/article/screen-readers-display-none.php and

 * https://www.w3.org/TR/WCAG-TECHS/H42.html for more information.

 */

#}

{%

  set classes = [

    'block',

    'block-menu',

    'navigation',

    'menu--' ~ derivative_plugin_id|clean_class,

  ]

%}

{% set heading_id = attributes.id ~ '-menu'|clean_id %}

<nav role="navigation" aria-labelledby="{{ heading_id }}"{{ attributes.addClass(classes)|without('role', 'aria-labelledby') }}>

  {# Label. If not displayed, we still provide it for screen readers. #}

  {% if not configuration.label_display %}

    {% set title_attributes = title_attributes.addClass('visually-hidden') %}

  {% endif %}

  {{ title_prefix }}

  <h2{{ title_attributes.setAttribute('id', heading_id) }}>{{ configuration.label }}</h2>

  {{ title_suffix }}

  {# Menu. #}

  {% block content %}

    {{ content }}

  {% endblock %}

</nav>