Examine source code of NNIN Generator

{
  "name": "NNIN Generator",
  "version": "1.3",
  "description": "Generate norwegian national identity numbers",
  "permissions": [
    "storage",
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "nnin32.png"
  },
  "icons": {
    "16": "nnin16.png",
    "32": "nnin32.png",
    "48": "nnin48.png",
    "128": "nnin128.png"
  },
  "manifest_version": 2
}