[bug-mailutils] Bug#520313: document .mu-size files on man page

[jidanni]

Package: mailutils
Version: 1:2.0+dfsg1-2
Severity: minor
X-debbugs-cc: address@hidden

[Discovery sequence:]
What a mystery those ~/Maildir/.mu-size files are.

What package could be putting them there, and under what conditions?

MUtt? MailUtils?
Hmmm, strings /usr/bin/mail shows lots of "mu"'s.
strace mail shows little.
zfgrep  .mu-s  on the docs shows
        * mailbox/amd.c (amd_append_message): Cache information about
        mailbox size in file .mu-size.
Ah ha!
If I were you I would call it .mailutils-size .

Anyway, please document it on the man page. (No mailutils Info on
Debian allowed. But coreutils Info OK.)

Also please note under what conditions it will appear.
My tests show that it won't if there is no mail and one uses mail(1).
One needs a test message.

It also apparently assumes it is the only mail user agent, but luckily
nothing bad seems to happen.

Say what advantage it gives mailutils vs. other programs.

I'll modify my shutdown unread mail warning scripts to only do
find ~/Maildir -type f ! -name .mu-size