Examine source code of CDN-JS Redirector

{
  "manifest_version": 2,
  "name": "JSModule Redirector",
  "version": "1.3.4",
  "description": "把各种JS库请求重定向到大型开源CDN",
  "permissions": [
    "<all_urls>",
    "tabs",
    "webRequest",
    "webRequestBlocking"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{60642337-cea5-48cc-a867-ec8691752150}"
    }
  }
}