Examine source code of PureInfo

{
  "name": "__MSG_appName__",
  "description": "__MSG_appDesc__",
  "version": "1.0.2",
  "manifest_version": 2,
  "default_locale": "en",
  "icons": {
    "16": "icons/icon_16.png",
    "32": "icons/icon_32.png",
    "48": "icons/icon_48.png",
    "64": "icons/icon_64.png",
    "128": "icons/icon_128.png"
  },
  "permissions": [
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://twitter.com/*"
      ],
      "run_at": "document_end",
      "css": [
        "content/main.css"
      ],
      "js": [
        "content/main.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "PureInfo",
    "default_popup": "popup/popup.html"
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "tqtifnypmb@gmail.com_pureinfo"
    }
  }
}