/resources/asset.proto 

--- v20/resources/asset.proto   2025-08-05 14:39:35.000000000 +0000
+++ v21/resources/asset.proto   2025-08-05 14:39:51.000000000 +0000
@@ -201,8 +201,12 @@
         business_message_asset = 51;

     // Immutable. An app deep link asset.
-    google.ads.googleads.v20.common.AppDeepLinkAsset app_deep_link_asset = 52
+    google.ads.googleads.v21.common.AppDeepLinkAsset app_deep_link_asset = 52
         [(google.api.field_behavior) = IMMUTABLE];
+
+    // Immutable. A YouTube video list asset.
+    google.ads.googleads.v21.common.YouTubeVideoListAsset
+        youtube_video_list_asset = 53 [(google.api.field_behavior) = IMMUTABLE];
   }
 }