Adam Sjøgren wrote:
> Eric writes:
>
> >> Are you sure Gnus is the program mangling it? It is mangled in your
> >> sent-folder?
> >>
> >> I just tried emailing myself an attachment and "from" was untouched
> >> - both in the copy in the sent-folder and the one I received
> >> through my local Postfix. (I tried both with disposition=attachment
> >> and inline, same result).
> >
> > FWIW, I tried it, and the "from" was capitalized in both the
> > received and sent version.
>
> Hm, interesting!

Thanks for your interest!

I did some more systematic tests.  The mangling is visible in the
locally saved version of the message, so it's definitely caused locally.
Moreover, the mangling seems to simply affect all the lines that begin
with a lower-case "from ", also in the main body.

The problem does *not* occur if I do not sign the message!  It *does*
occur when the message is signed either with an OpenPGP or with an
S/MIME key.

> Difference in versions? In storage type?
>
> (GNU Emacs 27.0.50 built from
> a7b7b85567f766ff510a5eaaaf32dbbbec15efd0, nnml).

GNU Emacs 24.5.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.11) of
2017-09-12 on hullmann, modified by Debian

It's not a new problem, I remember seeing it for the first time years
ago.

> I would guess that storage formats that have more than one email per
> file need to "escape" lines starting with "From " (as that is the
> separator), and maybe something then happens to lines starting with
> "from " as well?

It seems indeed have something to do with it, and not with SMTP headers.

> If you view the raw article, what does the line look like then?

I attach the pristine mbox file of a sent message (saved directly from
Gnus with 'o').  I only removed the host parts of email addresses.  The
MD5 sum of the attached file is ec7588fe8704b1d48aba09976894bc2e.

I am signing this mail, so let's see what will happen:
From this time forward, you will service us.

Christoph