Examine source code of QRWind

{
  "name": "QRWind",
  "version": "1.0.1",
  "description": "Generate QR Code for any link of webpage for free",
  "manifest_version": 2,
  "icons": {
    "16": "assets/images/icon16.png",
    "32": "assets/images/icon32.png",
    "48": "assets/images/icon48.png",
    "128": "assets/images/icon128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "browser_style": true
  },
  "permissions": [
    "tabs"
  ]
}