How specific must Copyright be?

[Birger Schacht <birger@rantanplan.org>]

Dear mentors,

I ITP (#929666) a software that lacks a copyright statement. I asked
upstream to clarify the copyright in the LICENSE file and upstream now
plans to use
> Copyright 2018-2019 github.com/containers authors
as a copyright statement. This seems a bit vague to me, in my experience
the copyright statement usually refers to persons or legal entities.
Would a copyright statement like the one above be acceptable in a
d/copyright file? Is it even legally valid?

cheers,
Birger