these 2 derivations will be built:
  /nix/store/k7qwsivcc866rg5n8l36zcjpygjdfr0y-rootfs-ubuntu-26_04.tar.drv
  /nix/store/9lgv5v2jrzajgg4p6xyhddfz43zvrj90-container-test-ubuntu-26-04-existing-files.drv