Examine source code of GitHub Widener

{
  "manifest_version" : 2 ,
  "name" : "GitHub Widener",
  "version" : "0.5",
  "description" : "Expands the GitHub code pane to the full window width.",
  "homepage_url" : "https://github.com/danstewart/github-widener",
  "icons" : {
    "48" : "icons/gh-widener-48.png"
  },
  "permissions" : [
    "history" ,
    "tabs" 
  ],
  "background" : {
    "scripts" : [
      "background.js" 
    ]
  },
  "browser_action" : {
    "default_icon" : {
      "16" : "icons/gh-widener-48.png",
      "32" : "icons/gh-widener-48.png"
    }
  },
  "content_scripts" : [
    {
      "matches" : [
        "*://github.com/*" ,
        "*://gist.github.com/*" 
      ],
      "js" : [
        "widener.js" 
      ]
    }
  ]
}