diff --git a/src/spicelib/analysis/cktsgen.c b/src/spicelib/analysis/cktsgen.c
index 7d3a082d6..249e99964 100644
--- a/src/spicelib/analysis/cktsgen.c
+++ b/src/spicelib/analysis/cktsgen.c
@@ -9,7 +9,8 @@ Copyright 1991 Regents of the University of California.  All rights reserved.
 #include "ngspice/ifsim.h"
 #include "ngspice/sensgen.h"
 
-	/* XXX */
+/* Used by sensitivity code in cktsens.c  */
+
 extern char	*Sfilter;
 
 int set_model(sgen *);