Issue #2407733 by mortendk, rteijeiro, sivaji@knackforge.com: Remove classes from system templates i*.html.twig

core/modules/system/templates/image.html.twig

@@ -12,9 +12,4 @@
  * @ingroup themeable
  */
 #}
-{%
-set classes = [
-  style_name ? 'image-style-' ~ style_name|clean_class,
-]
-%}
-<img{{ attributes.addClass(classes) }} />
+<img{{ attributes }} />

core/modules/system/templates/item-list.html.twig

@@ -19,7 +19,7 @@
  */
 #}
 {%- if items or empty -%}
-  <div class="item-list">
+  <div>
     {%- if title is not empty -%}
       <h3>{{ title }}</h3>
     {%- endif -%}

core/themes/classy/templates/system/indentation.html.twig

@@ -1,20 +0,0 @@
-{#
-/**
- * @file
- * Default theme implementation for a set of indentation divs.
- *
- * These <div> tags are used for drag and drop tables.
- *
- * Available variables:
- * - size: Optional. The number of indentations to create.
- *
- * @ingroup themeable
- */
-#}
-<!--
-THIS FILE IS NOT USED AND IS HERE AS A STARTING POINT FOR CUSTOMIZATION ONLY.
-See https://api.drupal.org/api/function/theme_indentation/8 for details.
-After copying this file to your theme's folder and customizing it, remove this
-HTML comment.
--->
-{% for i in 1..size if size > 0 %}<div class="indentation">&nbsp;</div>{% endfor %}