Examine source code of QR Sharer

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "QR Share",
  "description": "QR share is a quick add on to convert the link on your computer into qr code so you can scan it with your phone and visit the same on phone. It is useful in case when you are not using your computer or not logged in on both devices with same email account.",
  "background": {
    "scripts": [
      "custom.js"
    ]
  },
  "main": "index.html",
  "browser_action": {
    "default_icon": "qr_share.png",
    "default_popup": "index.html",
    "default_title": "QR Share"
  },
  "engines": {
    "firefox": ">=38.0a1"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "background",
    "http://*/*",
    "https://*/*",
    "notifications",
    "alarms",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "clipboardRead"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a1ea1ab0-2d19-4b09-9dc1-782339c1d6d7}"
    }
  }
}