diff --git a/src/wp-admin/includes/update-core.php b/src/wp-admin/includes/update-core.php
index fd0032601fc1c..9b6ece8d21a94 100644
--- a/src/wp-admin/includes/update-core.php
+++ b/src/wp-admin/includes/update-core.php
@@ -765,6 +765,11 @@
 	'wp-admin/images/about-header-freedoms.svg',
 	'wp-admin/images/about-header-contribute.svg',
 	'wp-admin/images/about-header-background.svg',
+	// 6.6
+	'wp-includes/blocks/block/editor.css',
+	'wp-includes/blocks/block/editor.min.css',
+	'wp-includes/blocks/block/editor-rtl.css',
+	'wp-includes/blocks/block/editor-rtl.min.css',
 );
 
 /**