Examine source code of FB game feed hider

{
  "description": "hides right column where game feed is present",
  "manifest_version": 2,
  "name": "FB game feed hider",
  "version": "1.0",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.facebook.com/*"
      ],
      "js": [
        "fb.js"
      ],
      "css": [
        "fb.css"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "*://*.facebook.com/*"
      ],
      "js": [
        "fb.js"
      ],
      "css": [
        "fb.css"
      ],
      "run_at": "document_idle"
    },
    {
      "matches": [
        "*://*.facebook.com/*"
      ],
      "js": [
        "fb.js"
      ],
      "css": [
        "fb.css"
      ],
      "run_at": "document_end"
    }
  ]
}