Examine source code of Easter Egg Cross - Animated

{
  "theme": {
    "images": {
      "theme_frame": "FirefoxPersona-BLZ-EasterEggCross-Animated-2.png"
    },
    "colors": {
      "frame": "#542da0",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Easter Egg Cross - Animated",
  "manifest_version": 2,
  "description": "This animation illustrates how to make an Easter egg shape.  Start by making a cross for guidance, then draw four circles on separate layers in your image editor, starting at the center of the cross. Use a single selection box to delete excess parts of the circles, leaving a perfectly shaped egg!  \n\nThe smallest circle can be moved if needed to line up with the large circles.  The top and bottom of the selection box should be located where the circles overlap; you will need to invert the selection before deleting from the two large circles.  Because of the simple geometry, this method gives you the same shape every time, no matter what size you make it.\n\nNote: There are a number of pauses which should reduce the demand on system resources.  \nTo rate or comment, login here:\n<a href=\"https://addons.mozilla.org/en-US/firefox/addon/easter-egg-cross-animated/#id=369102\" rel=\"nofollow\">https://addons.mozilla.org/en-US/firefox/addon/easter-egg-cross-animated/#id=369102</a> \nSee all my personas here:\n<a href=\"https://addons.mozilla.org/en-US/firefox/collections/BrianZ/personas/\" rel=\"nofollow\">https://addons.mozilla.org/en-US/firefox/collections/BrianZ/personas/</a> \n\n(spring, springtime, flowers, Easter, eggs, colorful, purple, yellow, green, blue, pastel, macro, closeup, religious, cross, holiday)\n(c) 2012 BrianZ  All Rights Reserved"
}