Examine source code of AntrixBirds

{
  "theme": {
    "images": {
      "theme_frame": "blue_bird.jpg"
    },
    "colors": {
      "frame": "#25abac",
      "tab_background_text": "#cccccc"
    }
  },
  "version": "2.0",
  "name": "AntrixBirds",
  "manifest_version": 2,
  "description": "There is also my AntrixFox for Firefox"
}