Examine source code of CouponGum

{
  "manifest_version": 2,
  "name": "CouponGum",
  "description": "CouponGum is a new way to get the latest coupon codes at the click of a button.",
  "version": "1.0.0",
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "CouponGum"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "img/logo-16.png",
    "48": "img/logo-48.png",
    "128": "img/logo-128.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "activeTab"
  ]
}