various internal documentation updates

Hopefully this gives new hackers a better overview of
how the components relate to each other.

1 files changed, 2 insertions, 0 deletions

diff --git a/public-inbox-mda b/public-inbox-mda
index df8ca38c..73c4ae1c 100755
--- a/public-inbox-mda
+++ b/public-inbox-mda
@@ -1,6 +1,8 @@
 #!/usr/bin/perl -w
 # Copyright (C) 2013-2015 all contributors <meta@public-inbox.org>
 # License: AGPLv3 or later (https://www.gnu.org/licenses/agpl-3.0.txt)
+#
+# Mail delivery agent for public-inbox, run from your MTA upon mail delivery
 use strict;
 use warnings;
 my $usage = 'public-inbox-mda < rfc2822_message';