$ nix-env -u kicad
upgrading 'kicad-5.1.2' to 'kicad-5.1.6'
these derivations will be built:
  /nix/store/90pi73qm42c0mwjr04c8j5dbrhazpz7g-packages3d.drv
  /nix/store/p9icrj5pl3yma3xbsrna21frz2c0awqx-kicad-packages3d-150ff1caf0.drv
  /nix/store/ivdhsz3c5cbzn6r5c6s8arb3h8lyhi8r-kicad-5.1.6.drv
building '/nix/store/90pi73qm42c0mwjr04c8j5dbrhazpz7g-packages3d.drv'...

trying https://github.com/KiCad/kicad-packages3d/archive/150ff1caf0b01dc04c84f4f966f4f88fedfa8f8c.tar.gz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   164  100   164    0     0    728      0 --:--:-- --:--:-- --:--:--   728