Examine source code of Facebook Wipe

{
  "manifest_version": 2,
  "name": "Facebook Wipe",
  "version": "2.1",
  "description": "Wipes facebook's distracting content off the screen.",
  "icons": {
    "48": "icons/wipe.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://www.facebook.com/*"
      ],
      "js": [
        "wipe.js"
      ]
    }
  ]
}