/enums/asset_field_type.proto 

--- v20/enums/asset_field_type.proto    2025-08-05 14:39:36.000000000 +0000
+++ v21/enums/asset_field_type.proto    2025-08-05 14:39:44.000000000 +0000
@@ -128,5 +128,8 @@

     // The asset is linked for use as a tall portrait marketing image.
     TALL_PORTRAIT_MARKETING_IMAGE = 32;
+
+    // The asset is linked for use as related YouTube videos.
+    RELATED_YOUTUBE_VIDEOS = 33;
   }
 }