Examine source code of FB scroll lock

{
  "manifest_version": 2,
  "name": "FB scroll lock",
  "version": "1.3resigned1",
  "description": "Limits the scroll of facebook page",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.facebook.com/*"
      ],
      "js": [
        "scroll-lock.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{067388a3-90af-4231-838f-440c97e6b98c}"
    }
  }
}