nix/nixos/factorio-versions.json

{
  "x86_64-linux": {
    "headless": {
      "stable": {
        "name": "factorio_headless_x64-2.0.15.tar.xz",
        "needsAuth": false,
        "sha256": "cLRBy4B4EaYFhsARBySMHY164EO9HyNnX8kk+6qlONg=",
        "tarDirectory": "x64",
        "url": "https://factorio.com/get-download/2.0.15/headless/linux64",
        "version": "2.0.15"
      }
    }
  }
}