Examine source code of QR Code Generator

{
  "manifest_version": 2,
  "name": "QR Code Generator",
  "version": "0.4",
  "description": "Generates a QR code for the current tab's URL or selected text.",
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4fa4a924-b442-4016-ba9f-3073059b5e8e}"
    }
  }
}