Examine source code of Graydient Firefox

{
  "theme": {
    "images": {
      "theme_frame": "firefox-persona-03.jpg"
    },
    "colors": {
      "frame": "#f5f5f5",
      "tab_background_text": "#303030"
    }
  },
  "version": "2.0",
  "name": "Graydient Firefox",
  "manifest_version": 2,
  "description": "Solid grey with slight gradient and firefox logo to the right"
}