Examine source code of Update Wbbpe.org

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Modify Wbbpe.org",
  "version": "0.2.47resigned1",
  "description": "add customised links to wbbpe",
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "http://*.wbbpe.org/*",
        "http://*.wbssc.gov.in/resultkps.php"
      ]
    }
  ],
  "author": "Pratyush Vashisht",
  "browser_specific_settings": {
    "gecko": {
      "id": "{ec650ba0-e6d7-4163-a3b6-ff75f9cb1542}"
    }
  }
}