bug#39553: 28.0.50; ada mode was removed

[Eli Zaretskii]

> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Tue, 8 Sep 2020 15:09:35 +0000
> Cc: larsi@gnus.org, 39553@debbugs.gnu.org, nick@nicksavage.ca
> 
> Right.  Sorry to not be more clear, but what I mean more specifically is
> that I don't understand what needs doing here.
> 
> I suppose `M-x list-packages U' should consider also built-in packages.
> 
> Anything else?

Doesn't package.el maintain some information about packages being
installed?  If so, how and where do you maintain that information for
packages that come from the tarball?

IOW, packages installed by package.el go to a special directory and
are handled specially by the startup code, something that is not true
for a built-in package.  This needs rectifying in some way.  I don't
know enough about package.el to give more specific and detailed
advice, sorry.