Examine source code of Document Previewer

{
  "manifest_version": 2,
  "name": "Document Previewer",
  "version": "2.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "docpre@hk.docpre"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "*://*/*.*"
  ],
  "web_accessible_resources": [
    "/redir.html",
    "/redir.js"
  ]
}