bug#59609: 29.0.50; [PATCH] Better advertise (Non-)GNU ELPA in emacs manual

[Stefan Kangas <stefankangas@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

> It's a good starting point, but the copyright assignment issue is not
> the only issue (not even the main one, from my POV).  The main issue
> with NonGNU ELPA, IMO, is that packages there don't necessarily adhere
> to the Emacs coding conventions, are not supervised by the Emacs
> maintainers, and do not have to coordinate their development decisions
> with the Emacs team.  So their integration into Emacs could be less
> seamless than that of packages from GNU ELPA.

Thanks, based on that I ended up with this:

modified   doc/emacs/package.texi
@@ -35,10 +35,20 @@ Packages
 name of a package, and displays a help buffer describing the
 attributes of the package and the features that it implements.

-  By default, Emacs downloads packages from a package archive
-maintained by the Emacs developers and hosted by the GNU project.
-Optionally, you can also download packages from archives maintained by
-third parties.  @xref{Package Installation}.
+  By default, Emacs downloads packages from GNU ELPA
+(@url{https://elpa.gnu.org/}) and NonGNU ELPA
+(@url{https://elpa.nongnu.org/}), two package archives maintained by
+the Emacs developers and hosted by the GNU project.  @dfn{GNU ELPA}
+contains packages that are available for use with Emacs, but are
+distributed separately from Emacs itself.  @dfn{NonGNU ELPA} contains
+a selection of third-party packages that are not supervised by the
+Emacs maintainers, do not necessarily adhere to the Emacs coding
+conventions, and do not coordinate their development decisions with
+the Emacs team.  They have been selected to be useful to many people,
+but their integration into Emacs could be less seamless than that of
+packages from GNU ELPA.  Optionally, you can also download packages
+from archives maintained by third parties.  @xref{Package
+Installation}.