Fascinating mailing list bug

[jdow]

After some years of no activity the packages list came alive with a noisier than 
LKML level of messages. So I decided to vanish from the list.

I looked at the headers of one of the updates emails and found this sequence:
===8<---
List-Id: Fedora Package Announcements <package-announce.lists.fedoraproject.org>
Archived-At: 
https://lists.fedoraproject.org/archives/list/[e-mail]/message/37PW452NQQPCRB5VAE6EXXPXKSTGWTG4/
List-Archive: 
https://lists.fedoraproject.org/archives/list/[e-mail]/
List-Help: 
List-Post: 
List-Subscribe: 
https://lists.fedoraproject.org/admin/lists/[e-mail],
    
List-Unsubscribe: 
https://lists.fedoraproject.org/admin/lists/[e-mail],
    
===8<---

So I dutifully emailed mailto:[e-mail].

===8<---
To: "mailto:package-announce-leave"@lists.fedoraproject.org
From: jdow 
Subject: unsubscribe
Message-ID: 
Date: Sat, 2 Jul 2016 13:34:27 -0700
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101
  Thunderbird/45.1.1
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
X-ELNK-Trace: 
bb89ecdb26a8f9f24d2b10475b571120570d22d52f4c61f59279cb3af55292e2d8ba5666b9b3d6db350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c
X-Originating-IP: 68.183.58.6

unsubscribe
===8<---

That was apparently the wrong thing to do. I got this in reply:

===8<---
This is the mail system at host smtp-mm-ib01.fedoraproject.org.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<"mailto:package-announce-leave"@lists.fedoraproject.org>: host
     mailman01.vpn.fedoraproject.org[192.168.1.118] said: 550 5.1.1
     : Recipient address
     rejected: User unknown in local recipient table (in reply to RCPT TO
     command)
===8<---

Either correct your headers, make lists.fedoraproject.org grow the proper 
username, or otherwise rectify your error before one loses her basic faith in 
the integrity of RedHat's basic bug elimination 101 abilities.

Shame on you.

{o.o}