Copy comment.html.twig template from Claro.

modules/core/ui/theme/farm_ui_theme.module

@@ -37,6 +37,13 @@ function farm_ui_theme_theme($existing, $type, $theme, $path) {
   ];
 }
 
+/**
+ * Implements hook_theme_registry_alter().
+ */
+function farm_ui_theme_theme_registry_alter(&$theme_registry) {
+  $theme_registry['comment']['path'] = \Drupal::service('extension.list.module')->getPath('farm_ui_theme') . '/templates';
+}
+
 /**
  * Implements hook_theme_suggestions_HOOK().
  */
@@ -143,7 +150,6 @@ function farm_ui_theme_gin_content_form_routes() {
  * Implements hook_entity_type_build().
  */
 function farm_ui_theme_entity_type_build(array &$entity_types) {
-
   // Override the default add and edit form class.
   $target_entity_types = [
     'asset' => AssetForm::class,

modules/core/ui/theme/templates/comment.html.twig

@@ -0,0 +1,115 @@
+{#
+/**
+ * @file
+ * Theme override for comments.
+ *
+ * Available variables:
+ * - author: (optional) Comment author. Can be a link or plain text.
+ * - content: The content-related items for the comment display. Use
+ *   {{ content }} to print them all, or print a subset such as
+ *   {{ content.field_example }}. Use the following code to temporarily suppress
+ *   the printing of a given child element:
+ *   @code
+ *   {{ content|without('field_example') }}
+ *   @endcode
+ * - created: (optional) Formatted date and time for when the comment was
+ *   created. Preprocess functions can reformat it by calling
+ *   DateFormatter::format() with the desired parameters on the
+ *   'comment.created' variable.
+ * - changed: (optional) Formatted date and time for when the comment was last
+ *   changed. Preprocess functions can reformat it by calling
+ *   DateFormatter::format() with the desired parameters on the
+ *   'comment.changed' variable.
+ * - permalink: Comment permalink.
+ * - submitted: (optional) Submission information created from author and
+ *   created during template_preprocess_comment().
+ * - user_picture: (optional) The comment author's profile picture.
+ * - status: Comment status. Possible values are:
+ *   unpublished, published, or preview.
+ * - title: (optional) Comment title, linked to the comment.
+ * - attributes: HTML attributes for the containing element.
+ *   The attributes.class may contain one or more of the following classes:
+ *   - comment: The current template type; e.g., 'theming hook'.
+ *   - by-anonymous: Comment by an unregistered user.
+ *   - by-{entity-type}-author: Comment by the author of the parent entity,
+ *     eg. by-node-author.
+ *   - preview: When previewing a new or edited comment.
+ *   The following applies only to viewers who are registered users:
+ *   - unpublished: An unpublished comment visible only to administrators.
+ * - 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.
+ * - content_attributes: List of classes for the styling of the comment content.
+ * - title_attributes: Same as attributes, except applied to the main title
+ *   tag that appears in the template.
+ * - threaded: A flag indicating whether the comments are threaded or not.
+ *
+ * These variables are provided to give context about the parent comment (if
+ * any, optional):
+ * - parent_comment: Full parent comment entity (if any).
+ * - parent_author: Equivalent to author for the parent comment.
+ * - parent_created: Equivalent to created for the parent comment.
+ * - parent_changed: Equivalent to changed for the parent comment.
+ * - parent_title: Equivalent to title for the parent comment.
+ * - parent_permalink: Equivalent to permalink for the parent comment.
+ * - parent: A text string of parent comment submission information created from
+ *   'parent_author' and 'parent_created' during template_preprocess_comment().
+ *   This information is presented to help screen readers follow lengthy
+ *   discussion threads. You can hide this from sighted users using the class
+ *   visually-hidden.
+ *
+ * These two variables are provided for context:
+ * - comment: Full comment object.
+ * - commented_entity: Entity the comments are attached to.
+ *
+ * @see template_preprocess_comment()
+ */
+#}
+{% if threaded %}
+  {{ attach_library('claro/classy.indented') }}
+{% endif %}
+{%
+  set classes = [
+    'comment',
+    'js-comment',
+    status != 'published' ? status,
+    comment.owner.anonymous ? 'by-anonymous',
+    author_id and author_id == commented_entity.getOwnerId() ? 'by-' ~ commented_entity.getEntityTypeId() ~ '-author',
+  ]
+%}
+<article{{ attributes.addClass(classes) }}>
+  {#
+    Hide the "new" indicator by default, let a piece of JavaScript ask the
+    server which comments are new for the user. Rendering the final "new"
+    indicator here would break the render cache.
+  #}
+  <mark class="hidden" data-comment-timestamp="{{ new_indicator_timestamp }}"></mark>
+
+  {% if submitted %}
+    <footer class="comment__meta">
+      {{ user_picture }}
+      <p class="comment__submitted">{{ submitted }}</p>
+
+      {#
+        Indicate the semantic relationship between parent and child comments for
+        accessibility. The list is difficult to navigate in a screen reader
+        without this information.
+      #}
+      {% if parent %}
+        <p class="parent visually-hidden">{{ parent }}</p>
+      {% endif %}
+
+      {{ permalink }}
+    </footer>
+  {% endif %}
+
+  <div{{ content_attributes.addClass('content') }}>
+    {% if title %}
+      {{ title_prefix }}
+      <h3{{ title_attributes }}>{{ title }}</h3>
+      {{ title_suffix }}
+    {% endif %}
+    {{ content }}
+  </div>
+</article>