reverted:
--- b/core/modules/system/system.module
+++ a/core/modules/system/system.module
@@ -256,14 +256,6 @@
 /**
  * Implements hook_theme_suggestions_HOOK().
  */
-function system_theme_suggestions_item_list(array $variables) {
-  $types = ['ul', 'ol', 'inline'];
-  return theme_get_suggestions($types, 'item_list');
-}
-
-/**
- * Implements hook_theme_suggestions_HOOK().
- */
 function system_theme_suggestions_page(array $variables) {
   if (\Drupal::service('path.matcher')->isFrontPage()) {
     $path_args = [''];
diff -u b/core/modules/system/templates/inline-list.html.twig b/core/modules/system/templates/inline-list.html.twig
--- b/core/modules/system/templates/inline-list.html.twig
+++ b/core/modules/system/templates/inline-list.html.twig
@@ -25 +24,0 @@
-
only in patch2:
unchanged:
--- /dev/null
+++ b/core/themes/classy/templates/dataset/inline-list.html.twig
@@ -0,0 +1,30 @@
+{#
+/**
+ * @file
+ * Theme override for an inline list of items.
+ *
+ * Available variables:
+ * - items: A list of items. Each item contains:
+ *   - attributes: HTML attributes to be applied to each list item.
+ *   - value: The content of the list element.
+ * - separator: A string to separate list items.
+ * - attributes: HTML attributes to be applied to the list.
+ * - empty: A message to display when there are no items. Allowed value is a
+ *   string or render array.
+ *
+ * @see template_preprocess_inline_list()
+ *
+ * @ingroup themeable
+ */
+#}
+{%- if items or empty -%}
+  {%- if items -%}
+    <span{{ attributes }}>
+      {%- for item in items -%}
+        <span{{ item.attributes }}>{{ item.value }}</span>
+      {%- endfor -%}
+    </span>
+  {%- else -%}
+    {{- empty -}}
+  {%- endif -%}
+{%- endif %}