Suspiciously you're the one who's trying to be included into every Nix{,OS} conversation with alternative facts easily disproved with a 5 second ddg search. Also, you're writing this to friggin rycee 1 2 3, which is just a cherry on top. Sincerely, someone who's mastered time travel because apparently running NixOS 15.09 on a desktop was not possible in this timeline. Oh wait whoops people have been running NixOS on desktop since 2007.

(honestly, you must be trolling, I just don't see any other reason to do this shit.)

Desktop packages haven't even been a part of the Nix repos for 10 years.

Yes they have? Why are you just making shit up.

https://github.com/NixOS/nixpkgs/tree/15.09-beta/pkgs/desktops/plasma-5.3