Examine source code of speedometer animated

{
  "name": "speedometer",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "1479297505_tumblr_n5xuiilE271r5mggso1_500.gif"
    },
    "colors": {
      "frame": "rgba(0, 0, 0, 0.99)",
      "tab_background_text": "rgba(228, 240, 8, 0.78)",
      "toolbar": "rgba(0, 0, 0, 0)",
      "bookmark_text": "rgba(230, 28, 28, 0.77)",
      "toolbar_field": "rgba(0, 0, 0, 0)",
      "toolbar_field_text": "rgba(232, 232, 225, 1)"
    }
  }
}