email/tools: WG unsubscribe notification

[Toerless Eckert <[e-mail]>]

Dear IETF email team

(As ANIMA WG chair) i just received 31 emails of the type

> Date: Wed, 18 May 2022 09:00:01 -0700
> From: [e-mail]
> To: [e-mail]
> Subject: Anima unsubscribe notification
>
> [e-mail] has been removed from Anima. (disabled address)

I don't remember i have seen this before over the years. If this is a new feature,
and there was an email explaining it, i must have missed the email or URL
explaining it. Pointer welcome. 

This looks like a nice feature to eliminate old junk, except that i am worried
(after the recent incident with my own emails spam filter caused unsubscription),
how exactly the condition "disabled address" is determined.

In general, i am not a big fan of what is probably intended as a user-friendly
explanation such as "disabled address" without also providing the actual
root cause diagnostic. It ony gives me "Admiral Failure" frustration.

When i sent an email to one of the addresses i did know to be obsolete,
SMTP gave me:

<[e-mail]>: host mx5.somewhere.com[1xx.xx.xx.xxx] said: 551                                            
    5.1.1 <[e-mail]>: Recipient address rejected: Failed                                            
    recipient validation check.: host 127.0.0.1[127.0.0.1] said: 554 5.7.1                                             
    recipient verify from ldap failed (in reply to RCPT TO command) (in reply                                          
    to RCPT TO command)  

I would appreciate if this error indication would also be included in the
"Unsubscribe notification" email, so that we as WG chairs (or other mailing
list owners) can do our best to help finding false positives.

Cheers
    Toerless