Examine source code of Tetrys

{
  "browser_action": {
    "default_icon": "images/icon.png",
    "default_popup": "index.html"
  },
  "description": "A fun game that plays in a popup",
  "icons": {
    "16": "images/icon.png",
    "48": "images/icon.png",
    "128": "images/icon.png"
  },
  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsOcVPnMLIQC2gYxYMDvVAuO7S/7ilsoJNSxYuKRSCO8t/N+k9Bv1RpWpZFJNw2GGJBAkTZJmvLfJeqYWfvtdVMLx0Ix1Gpo4EXD3DGQJVOuTIui8EqhLQL9CzKDpsV3FJ8SiGjD7EdmgDBkJ+k4IiqTsaJPrZi1T9WY5dprvqFvBqBOYWa1/jzC2HuOJApJKAJyENyh7Lp8cEbx3cFTX3IVYylEEtxfyBPW//SgCynbk8i5sxrpGK8LfOV+PTgOVSz1vceZElrKaobTSxWyEZIHTaJZx0Ike5MzUgsqlnkZXiGR+uYI/dutOFrf72aXtb6EP4dub5VBPi7lkc+vFsQIDAQAB",
  "manifest_version": 2,
  "name": "Tetrys",
  "offline_enabled": true,
  "short_name": "Tetrys",
  "version": "2.2.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "{563fcf3f-8d10-40aa-98ae-cf628113e30d}"
    }
  }
}