Examine source code of WhatIP

{
  "manifest_version": 2,
  "name": "WhatIP",
  "version": "0.3resigned1",
  "author": "aokami",
  "homepage_url": "https://github.com/aoikeiichi/WebExt-WhatIP",
  "description": "Shows Ip of host with latest webExt tech.",
  "permissions": [
    "tabs",
    "webRequest",
    "<all_urls>"
  ],
  "page_action": {
    "browser_style": true,
    "default_icon": {
      "16": "icons/vX-16.png",
      "32": "icons/vX-32.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b0a89da7-f70c-46bf-bb75-3bf5266107f7}"
    }
  }
}