Subject: Mention how to configure module on Debian

--- a/SessionX.pm
+++ b/SessionX.pm
@@ -572,8 +572,9 @@
 
 =item config
 
-Use predefiend config from Apache::SessionX::Config, which is defined by
-Makefile.PL
+Use predefiend config from Apache::SessionX::Config, which is configured
+at package installation time.  On Debian, these may be altered by running
+C<dpkg-reconfigure libapache-sessionx-perl>.
 
 
 =item object_store