my_hdr X-Operating-System: `lsb_release -a | grep "^Description:" | sed "s/Description:[\t ]*//"`

# h key show all headers
hdr_order Date From X-Sender Old-Return-Path Reply-To Mail-Followup-To To Cc Bcc
hdr_order Delivered-To Subject In-Reply-To X-Mailing-List Mailing-List
hdr_order X-Operating-System X-Mailer User-Agent X-GPG- X-PGP-
unignore  Date From X-Sender Old-Return-Path Reply-To Mail-Followup-To To Cc Bcc
unignore  Delivered-To Subject In-Reply-To X-Mailing-List Mailing-List
unignore  X-Operating-System X-Mailer User-Agent X-GPG- X-PGP-

set sort = reverse-date-received
set edit_headers = yes
set askcc = yes
set reply_to = ask-yes
set copy = yes
set include

set forward_format = "Fwd: %s"

set editor = '/usr/bin/vim -c "set textwrap=72" -c "set wrap" -c "?^$"'                  # vi bien sûr

alternative_order text/html text/enriched text/plain
set beep_new = yes
set include=yes
set abort_nosubject = ask-yes
set abort_unmodified = ask-yes

set header_cache =~/.mutt/cache/headers
set message_cachedir =~/.mutt/cache/bodies
set certificate_file=~/.mutt/certificates