Examine source code of The Nightmare

{
  "name": "The Nightmare",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "1024px-John_Henry_Fuseli_-_The_NightmareFXD.jpg"
    },
    "colors": {
      "frame": "rgba(82, 30, 32, 1)",
      "tab_background_text": "rgba(242, 83, 83, 1)",
      "toolbar": "rgba(135, 86, 86, 1)",
      "bookmark_text": "rgba(255, 0, 0, 1)",
      "toolbar_field": "rgba(237, 204, 204, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2dda0bda-8437-4d0f-a0e7-0466ef07bc74}"
    }
  }
}