Examine source code of FbookHideAd

{
  "manifest_version": 2,
  "name": "FbookHideAd",
  "version": "1.8",
  "description": "Continuously tries to hide suggested and sponsored posts (adverts) on facebook",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.facebook.com/*"
      ],
      "js": [
        "jquery.js",
        "fbook.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{22ef3052-588c-4fc3-abaf-a4d159b5cc70}"
    }
  }
}