Examine source code of Night Cityscape

{
  "theme": {
    "images": {
      "theme_frame": "City-Header.jpg"
    },
    "colors": {
      "frame": "#ffffff",
      "tab_background_text": "#cccccc"
    }
  },
  "version": "2.0",
  "name": "Night Cityscape",
  "manifest_version": 2,
  "description": "Night cityscape with glowing city lights background and stars."
}