Examine source code of Firefox SimplyBlue

{
  "theme": {
    "images": {
      "theme_frame": "firefox_simple.png"
    },
    "colors": {
      "frame": "#828282",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "Firefox SimplyBlue",
  "manifest_version": 2,
  "description": "Simple, clean, effective.\n\nFirefox SimplyBlue is elegant and wont clutter up your menu bar."
}