Examine source code of PQR Codes

{
  "manifest_version": 2,
  "name": "Personal QR Codes",
  "version": "1.1",
  "description": "You can easily generate a QR code, edit and share it.",
  "homepage_url": "https://pqr.codes",
  "icons": {
    "32": "/icons/favicon.png"
  },
  "permissions": [
    "webRequest",
    "<all_urls>"
  ],
  "browser_action": {
    "default_icon": "/icons/favicon.png",
    "default_title": "PQR.Codes",
    "default_popup": "html/main.html"
  }
}