Examine source code of Bookmark Time Machine

{
  "name": "Bookmark Time Machine",
  "version": "0.2.4resigned1",
  "manifest_version": 2,
  "description": "Take a trip in time to see what you have bookmarked in the past !",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": "icons/icon19.png",
    "default_title": "Bookmark Time Machine"
  },
  "permissions": [
    "bookmarks",
    "chrome://favicon/",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{fc441a8f-c54b-462a-a728-8735919d6ac2}"
    }
  }
}