Examine source code of Firefox Chocolate Scratch

{
  "theme": {
    "images": {
      "theme_frame": "ff_chocolate_scratch_header.png"
    },
    "colors": {
      "frame": "#cccccc",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Firefox Chocolate Scratch",
  "manifest_version": 2,
  "description": "Theme gives a nice \"rustic\" appearance behind the transparent buttons. Also, compatible for vertical sidebar users."
}