Examine source code of dark puzzle

{
  "theme": {
    "images": {
      "theme_frame": "darkpuzzle.jpg"
    },
    "colors": {
      "frame": "#733333",
      "tab_background_text": "#fcf9f9"
    }
  },
  "version": "2.0",
  "name": "dark puzzle",
  "manifest_version": 2,
  "description": "a dark colored puzzle"
}