Examine source code of Vector Spring

{
  "theme": {
    "images": {
      "theme_frame": "cherryblossom1_head.png"
    },
    "colors": {
      "frame": "#51b9d9",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Vector Spring",
  "manifest_version": 2,
  "description": "cherry blossom vector with blue striped background\n\nby <a href=\"https://outgoing.prod.mozaws.net/v1/dc4647014754cf8ac6386e541c176957582830d053803d241569d6e29a44cdc5/http%3A//twobeers.net\" rel=\"nofollow\">twobeers.net</a>"
}