Examine source code of Full Width Wikipedia

{
  "manifest_version": 2,
  "name": "Full Width Wikipedia",
  "version": "1.1",
  "description": "Remove the new Wikipedia style to use the previous/historical full sized version.",
  "icons": {
    "48": "icons/icon-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.wikipedia.org/*"
      ],
      "js": [
        "js/fullsizewiki.js"
      ]
    }
  ]
}