diff --git a/source/org/thdl/tib/text/tibwn.ini b/source/org/thdl/tib/text/tibwn.ini
index 6479603..5cc584b 100644
--- a/source/org/thdl/tib/text/tibwn.ini
+++ b/source/org/thdl/tib/text/tibwn.ini
@@ -9,6 +9,9 @@
 // If you change the Wylie here, it can break the ACIP->TMW and
 // ACIP->Unicode conversion.  So keep ACIPRules in sync with this, and be
 // sure to run 'ant clean check' after your change.
+//
+// DuffPaneTest ensures that the na-ro column truly contains na-ros,
+// by the way.
 
 <?Input:Punctuation?>
 //_~32,1~0,32