@sepples I haven't used NixOS, but as they don't have a policy to not include nonfree software, I'm not sure how much they bother to actually record the correct license and thus have `allowUnfree = false` work reliably (Gentoo with an adjusted ACCEPT_LICENSE is similar I guess, but Gentoo gets half the LICENSE's wrong somehow).

Guix is a fully free GNU/Linux distro that I've installed before, but not used much due to the inability of easily being able to customize compile time flags.

Someone is working on parameterized packages, so I guess I'll be able to switch to Guix once that's usable.