Examine source code of Close Similar Tabs

{
  "manifest_version": 2,
  "name": "Close Similar Tabs",
  "author": "Frank Wang",
  "version": "1.0.1resigned1",
  "applications": {
    "gecko": {
      "id": "ff-close-similar-tabs.git.webdkt@gmail.com"
    }
  },
  "description": "Close all similar tabs from same host",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "activeTab",
    "menus",
    "tabs"
  ]
}