On Wed, Apr 01, 2020 at 09:48:39AM +0200, H. Dieter Wilhelm wrote:
> Hello Emacs-26.3
> 
> Today I sent to myself an email from Outlook with a PDF attachment and I
> received an email with a winmail.dat attachement!  Never seen such a
> thing in my live.

This seems to be a TNEF (aka "Transport Neutral Encapsulation Format")
from Microsoft (God may have pity of their souls).

According to [1] there are a few options for normal folks to decode
that stuff.

> It seems that Gnus is just saving it as a winmail.dat file on the disc.
> What are you doing with such an abomination under GNU-Linux? ;-)

I try to get out of my way to avoid that stuff (that includes recommending
my customers to do the same -- think network effects and all that).

Cheers
[1] https://en.wikipedia.org/wiki/Transport_Neutral_Encapsulation_Format#Decoding

-- t