Examine source code of Cashback Charity

{
  "permissions": [
    "tabs",
    "webRequest",
    "webRequestBlocking",
    "*://*.amazon.de/*",
    "*://*.amazon.com/*",
    "*://*.amazon.fr/*",
    "*://*.amazon.co.uk/*",
    "*://*.amazon.co.jp/*",
    "*://*.amazon.ca/*",
    "*://*.amazon.cn/*",
    "*://*.amazon.it/*",
    "*://*.amazon.es/*",
    "*://*.amazon.in/*",
    "*://*.amazon.com.br/*",
    "*://*.amazon.com.mx/*",
    "*://*.amazon.com.au/*"
  ],
  "name": "cashback",
  "description": "Cashback Charity wants to make donation easy.",
  "version": "0.6.4",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "page_action": {
    "default_popup": "index.html",
    "default_icon": {
      "16": "images/icon-16.png",
      "32": "images/icon-32.png",
      "48": "images/icon-48.png",
      "128": "images/icon-128.png"
    }
  },
  "icons": {
    "16": "images/icon-16.png",
    "32": "images/icon-32.png",
    "48": "images/icon-48.png",
    "128": "images/icon-128.png"
  }
}