/enums/conversion_attribution_event_type.proto 

--- v20/enums/conversion_attribution_event_type.proto   2025-08-05 14:39:38.000000000 +0000
+++ v21/enums/conversion_attribution_event_type.proto   2025-08-05 14:39:43.000000000 +0000
@@ -40,5 +40,8 @@

     // The conversion is attributed to an interaction.
     INTERACTION = 3;
+
+    // The conversion is attributed to a 10s engaged view.
+    ENGAGED_VIEW = 4;
   }
 }