diff --git a/utils.py b/utils.py
index b1b44bb93..e36e20acb 100644
--- a/utils.py
+++ b/utils.py
@@ -1,5 +1,9 @@
 #! /usr/bin/env python
 
+# These methods are used by test.py and waf to look for and read the
+# .ns3rc configuration file, which is used to specify the modules that
+# should be enabled
+
 import os
 import sys