Examine source code of Cavernes

{
  "theme": {
    "images": {
      "theme_frame": "banniere_firefox.jpg"
    },
    "colors": {
      "frame": "#bbaa77",
      "tab_background_text": "#996600"
    }
  },
  "version": "2.0",
  "name": "Cavernes",
  "manifest_version": 2,
  "description": "For the Caverneux, the AC/DC fly"
}