Examine source code of YouTube New Tab

{
  "manifest_version": 2,
  "name": "YouTube New Tab",
  "version": "1.1.0",
  "description": "Adds a button to open YouTube videos in a new tab without having to middle click.",
  "icons": {
    "16": "images/icon16.png",
    "32": "images/icon32.png",
    "64": "images/icon64.png",
    "128": "images/icon128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ]
}