Examine source code of Lightning Castle

{
  "theme": {
    "images": {
      "theme_frame": "firefoxthingcopy.jpg"
    },
    "colors": {
      "frame": "#0b5c3c",
      "tab_background_text": "#a1ffd3"
    }
  },
  "version": "2.0",
  "name": "Lightning Castle",
  "manifest_version": 2,
  "description": "long exposure photograph taken while driving at night"
}