Examine source code of Factorio (fan creation)

{
  "name": "Factorio (fan creation)",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "background-image-logo.png"
    },
    "colors": {
      "frame": "rgba(49, 48, 49, 1)",
      "tab_background_text": "rgba(220, 199, 168, 1)",
      "bookmark_text": "rgba(227, 152, 39, 1)",
      "toolbar_field": "rgba(94, 182, 99, 1)",
      "toolbar_field_text": "rgba(36, 35, 36, 1)"
    }
  }
}