Hello,

I’m using emacs notmuch together with Gnus and I noticed that M-x 
compose-mail stopped working properly for me since.  I identified 
notmuch as culprit: (requre ’notmuch) sets the user-customizable 
variable mail-user-agent.  I believe that such behavior is not 
expected of emacs modules.

A patch [1] has been proposed to fix this in 2014, but never 
accepted.  Is there a reason why the problematic behavior has been 
kept?

Thanks,
Christoph

[1] 
http://notmuch.198994.n3.nabble.com/PATCH-emacs-do-not-change-users-mail-agent-configuration-td4032745.html