Richard Stallman <rms@gnu.org> writes:

>   > I see that mpv.el doesn't have a file COPYING in its repository.
>   > I'm not sure if that would be important to fix first.
> It is violating the GPL.  That's a problem that ought to be fixed --
> but fixing it won't be hard.
I've submitted a pull request and included a link to the post about
including it in NonGNU ELPA. I've also e-mailed rndusr (original author
of subed) about copyright assignment. Let's see how that goes!