Examine source code of Fox on Fire 2

{
  "name": "Fox on Fire",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "firefox_by_hungerartist.jpg"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 1)",
      "tab_background_text": "rgba(207, 64, 9, 1)",
      "toolbar": "rgba(228, 93, 20, 0.4)",
      "bookmark_text": "rgba(242, 153, 36, 1)",
      "toolbar_field": "rgba(196, 153, 108, 0.5)",
      "toolbar_field_text": "rgba(46, 28, 32, 1)"
    }
  }
}