Examine source code of historious extension

{
  "name": "historious extension",
  "short_name": "historious bookmarking extension",
  "version": "1.7",
  "manifest_version": 2,
  "options_ui": {
    "page": "options.html"
  },
  "description": "historio.us extension",
  "permissions": [
    "tabs",
    "notifications",
    "http://historio.us/*",
    "https://historio.us/*",
    "activeTab"
  ],
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_icon": "icon19.png",
    "default_title": "historify!"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}