Examine source code of Bookmark topper

{
  "manifest_version": 2,
  "name": "Bookmark topper",
  "version": "0.2.1",
  "author": "twevoli",
  "description": "Move bookmarks from the very bottom to the top",
  "icons": {
    "32": "icon-32.png",
    "64": "icon-64.png",
    "128": "icon-128.png"
  },
  "permissions": [
    "bookmarks"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{67d82663-b0b5-4cea-8c3f-8025451d606b}"
    }
  }
}