diff --git a/libmalcontent/app-filter-private.h b/libmalcontent/app-filter-private.h
index 42e97b3..c4f9b31 100644
--- a/libmalcontent/app-filter-private.h
+++ b/libmalcontent/app-filter-private.h
@@ -52,7 +52,7 @@ struct _MctAppFilter
 
   uid_t user_id;
 
-  gchar **app_list;  /* (owned) (array zero-terminated=1) */
+  gchar **app_list;  /* (not nullable) (owned) (array zero-terminated=1) */
   MctAppFilterListType app_list_type;
 
   GVariant *oars_ratings;  /* (type a{ss}) (owned non-floating) */