Examine source code of StackExchangeNotifications

{
  "author": "Guilherme Nascimento",
  "name": "StackExchangeNotifications",
  "description": "Show recent achievements and inbox messages from Stack Exchange",
  "version": "1.3.3",
  "manifest_version": 2,
  "default_locale": "en",
  "icons": {
    "16": "images/icon.png",
    "32": "images/icon-32px.png",
    "48": "images/icon-48px.png",
    "128": "images/icon-128px.png"
  },
  "browser_action": {
    "default_icon": "images/icon.png",
    "default_popup": "views/popup.html"
  },
  "options_ui": {
    "page": "views/options.html#config"
  },
  "background": {
    "scripts": [
      "js/stackexchangenotifications.js",
      "js/extends.js",
      "js/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://stackapps.com/*",
        "*://askubuntu.com/*",
        "*://superuser.com/*",
        "*://serverfault.com/*",
        "*://stackoverflow.com/*",
        "*://stackexchange.com/*",
        "*://*.stackapps.com/*",
        "*://*.askubuntu.com/*",
        "*://*.superuser.com/*",
        "*://*.serverfault.com/*",
        "*://*.stackoverflow.com/*",
        "*://*.stackexchange.com/*",
        "*://mathoverflow.net/*",
        "*://mathoverflow.com/*",
        "*://*.mathoverflow.net/*",
        "*://*.mathoverflow.com/*"
      ],
      "js": [
        "js/extends.js",
        "js/detectchanges.js",
        "js/gallery.js",
        "js/editor.js",
        "js/extras.js",
        "js/comments.js"
      ]
    },
    {
      "matches": [
        "*://chat.stackexchange.com/*",
        "*://chat.stackoverflow.com/*",
        "*://chat.meta.stackoverflow.com/*",
        "*://chat.meta.stackexchange.com/*"
      ],
      "js": [
        "js/pinchat.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "views/*",
    "css/*",
    "images/*"
  ],
  "permissions": [
    "*://stackexchange.com/*",
    "*://*.sstatic.net/*",
    "tabs"
  ]
}