Examine source code of nga-helper

{
  "manifest_version": 2,
  "name": "nga-helper",
  "version": "1.4.1",
  "description": "nga helper , icon from http://www.iconbeast.com",
  "icons": {
    "48": "icons/helper-48.png"
  },
  "permissions": [
    "activeTab",
    "downloads",
    "*://ngabbs.com/*",
    "*://img.nga.178.com/*",
    "*://*.nga.cn/*",
    "*://*.178.com/*",
    "*://*.ngacn.cc/*",
    "http://tva4.sinaimg.cn/*"
  ],
  "browser_action": {
    "default_icon": "icons/helper-32.png",
    "default_title": "NGA-Helper",
    "default_popup": "popup/list.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://ngabbs.com/*"
      ],
      "js": [
        "content_scripts/content-script.js",
        "js/template-web.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "js/jquery.min.js",
      "bg_scripts/background-script.js"
    ]
  },
  "cookies": [
    "*://ngabbs.com/",
    "*://img.nga.178.com/"
  ]
}