Index: tools/build/options/makeman
===================================================================
--- tools/build/options/makeman
+++ tools/build/options/makeman
@@ -1,8 +1,22 @@
 #!/bin/sh
 #
 # This file is in the public domain.
-#
 # $FreeBSD$
+#
+# This script is used to create the src.conf.5 man page, using template text
+# contained herein and the contents of the WITH_* and WITHOUT_* files in the
+# same directory. The WITH_* and WITHOUT_* files document the effect of the
+# /etc/src.conf knob of the same names.
+#
+# This script invokes "make showconfig" for each supported architecture
+# in order to determine, for each option, whether it the default setting is
+# always WITH, always WITHOUT, or is architecture-dependent. It also determines
+# and describes dependencies between options.
+#
+# Usage:
+#
+#     cd tools/build/options
+#     sh makeman > ../../../share/man/man5/src.conf.5
 
 set -o errexit
 export LC_ALL=C