Finish incomplete comments in prior revision. I was going to fix this

after I tested it, but didn't.

etc/defaults/rc.conf

@@ -21,6 +21,8 @@
 ###  Important initial Boot-time options  ####################
 ##############################################################
 
+# rc_debug can't be set here without interferring with rc.subr's setting it
+# when the kenv variable rc.debug is set.
 #rc_debug="NO"		# Set to YES to enable debugging output from rc.d
 rc_info="NO"		# Enables display of informational messages at boot.
 rc_startmsgs="YES" 	# Show "Starting foo:" messages at boot

etc/rc.subr

@@ -2120,7 +2120,8 @@ _echoonce()
 }
 
 # If the loader env variable rc.debug is set, turn on debugging. rc.conf will
-# still override this, but /etc/defaults/rc.conf.a
+# still override this, but /etc/defaults/rc.conf can't unconditionally set this
+# since it would undo what we've done here.
 if kenv -q rc.debug > /dev/null ; then
 	rc_debug=YES
 fi