Examine source code of Coupon Collector

{
  "manifest_version": 2,
  "name": "Coupon Collector",
  "version": "1.2",
  "description": "Automatically click coupon buttons on store webpages",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "128": "icons/icon-128.png"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "styles.css"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "Coupon Collector",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2cdcf80a-ddf4-4db5-9af8-ae04dbf870cb}"
    }
  }
}