As mentioned on the GPL guide as linked, the copyright notice is not about the COPYING file, but about the header in each source file. To quote:
This involves adding two elements to each source file of your program: a copyright notice (..)
The following The copyright notice chapter is about this part, not about COPYING. The The license files chapter is about COPYING. This file is copyrighted, but to GNU, not to us. After all, we didn't write it ;)
I am not sure if @panosalevropoulos has any source that disagrees with this conclusion, but this how I read that guide. Additionally, to me it would also be weird to add a copyright notice to a file that we didn't write. But IANAL, so who knows :)
Going to close this ticket for now; if you have any additional information, please do let us know! Tnx!
@TrueBrain I agree that my original post was incorrect. The copyright notice should not be included in the COPYING file. But the issue remains. At minimum there should be a copyright notice in the README or CREDITS file. Optimally, there would be a copyright notice in every code file header.
Currently, there is no copyright notice to be found on the project's page.