bug#33825: 25.2; , Failing to verify signature for ELPA debbugs package

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Mon, 16 Sep 2019 13:04:55 +0200
> Cc: 33825@debbugs.gnu.org, clemera <clemens.radermacher@posteo.de>
> 
> > I think this is notabug. We can always reopen it if needed.
> 
> Perhaps we could also add something about this issue to PROBLEMS?

Feel free to do that.

> How about also adding a recommendation to use https, as far as
> possible, for package archives?  I guess that could be added to both
> the doc string of package-archives and possibly also the manual.  That
> would help security and avoid issues such as these.

I'd leave this out of the manual.  Doc string should be enough.