Any additional flags passed to nixos-rebuild. If you are using flakes and use a local repo you can add [ "--update-input" "nixpkgs" "--commit-lock-file" ] to update nixpkgs.

[ ]

[
  "-I"
  "stuff=/home/alice/nixos-stuff"
  "--option"
  "extra-binary-caches"
  "http://my-cache.example.org/"
]