Steam

Aren't those all basically just standard ArchLinux packages? Are they modified in any way from their original PKGBUILD? Do those packages come with non public patches applied to them?

If they're just plain Arch packages, I don't see a problem with the implied need to go get them from Arch. Sure it would be nicer if you could just use their build system, but if you want the source for the bash binary they ship and it's the same unmodified upstream bash sources.

Can you point to a specific problematic package or component/binary/script that the GPL requires to be public that is not?

The things I find lol

https://gitlab.com/evlaV/holo-PKGBUILD/-/blob/master/images/fuck-you-1.jpg?ref_type=heads