diff --git a/docs/swab.1 b/docs/swab.1
index 42eef95..89cebb2 100644
--- a/docs/swab.1
+++ b/docs/swab.1
@@ -36,6 +36,7 @@ line:
 .RS
 printf 'hello world!\(rsn' | swab
 .RE
+.\" If you change this, make sure to change it in tests/bonsai/swab.mk too.
 
 Produces the following output: