More runtime file updates.
diff --git a/runtime/doc/todo.txt b/runtime/doc/todo.txt
index 8327884..94c0751 100644
--- a/runtime/doc/todo.txt
+++ b/runtime/doc/todo.txt
@@ -30,6 +30,8 @@
 							*known-bugs*
 -------------------- Known bugs and current work -----------------------
 
+Diff python and python3 code, some is missing in python3.
+
 Before release 7.3:
 - Rename vim73 branch to default (hints: Xavier de Gaye, 2010 May 23)