Examine source code of Bookmark2Toolbar

{
  "description": "Add a bookmark to the toolbar",
  "manifest_version": 2,
  "name": "Bookmark2Toolbar - 1/2",
  "version": "1.3.1",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/ico16.png",
      "32": "icons/ico32.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "86darv@gmail.com"
    }
  },
  "permissions": [
    "menus",
    "activeTab"
  ]
}