This reverts commits 9d0de0dc57ce97ab9cc3d73a66e914d718e4af3b, 27d2857a9927aa197b9679b9a2dcf59b97c06907. 'nix ping-store' is an experimental command so it doesn't work in Nix 2.4 unless you set 'experimental-features = nix-command' in nix.conf.
jupyter.kernels