[MlMt] "X-Envelope-to" - should be more visble

[Bill Cole]

On 2024-03-06 at 04:21:38 UTC-0500 (Wed, 06 Mar 2024 10:21:38 +0100)
Michael Nietzold <mailmate at lists.freron.com>
is rumored to have said:

> I have some spam mails which uses the `X-Envelope-to:` header

Can you quantify that? I see none in a corpus of a half-million messages 
going back to the 90's. But which headers are in your mail is an issue 
very much dependent on who your mailbox provider is.

The leading "X-" tells you that this is a header that someone thought 
was nice and invented on their own, and never changed to remove the X. 
You cannot rely on its presence or consistency unless you know who has 
decided to put that on some mail. Simply "Envelope-to" also exists on a 
tiny number of messages in the wild, and "Original-Recipient" is 
actually standardized 
(https://www.rfc-editor.org/rfc/rfc3798.html#section-2.3.) but is not 
widespread. Rather more widely implemented is the "X-Original-To" header 
which is implemented in multiple MTA/MDAs.

My guess is that the "X-Envelope-to" would logically hold the same 
meaning as those, but who really knows. It only makes sense to add such 
a header on final delivery or when a MTA modifies a SMTP envelope 
recipient.

> Some of them are don't have a `to:` header

Technically not wrong if at one time it had a Bcc.

> If I just search in the mail mate search box it not find this emails. 
> I need explicit use  `X-Envelope-to: myname at mydomain.com` to find it.

MailMate can search on any header, even those that only exist in one 
message, through the full search bar that you get to with the Search 
button. If you pull down the menu with header names, you will see 
"Other..." at the very end. Select that and you will get a full picker 
that allows you to select any header and optionally include them in the 
pull-down menu.

> What can I do that the normal search also include the `X-Envelope-to:` 
> header?

I don't think you can get the simple Search box to search non-standard 
headers. You can make it search all text and "common" headers, but this 
one isn't common.

> I would also like to see this header as a line in the mail view.

Not a lot of people would find that useful, given the general rarity of 
that specific header...

However, what would be great is if there was a better way to select 
which headers are in the standard displayed set. E.g. I almost always 
want to know what the Reply-To header is if it exists and there are 
mailing lists I am on which put the list address in the From header, 
moving the real From into some other header (often Reply-To) to allow 
them to add their own DKIM+DMARC authentication. I would like to see MM 
have a simple way to pick additional headers to show, because which ones 
are useful can be very site-specific and user-specific.

-- 
Bill Cole
bill at scconsult.com or billcole at apache.org
(AKA @grumpybozo and many *@billmail.scconsult.com addresses)
Not Currently Available For Hire