Examine source code of Youtube Customiser

{
  "manifest_version": 2,
  "version": "0.0.2",
  "short_name": "Youtube Custom",
  "name": "Youtube Customiser",
  "description": "Add and remove Youtube content panels as you wish.",
  "browser_action": {
    "default_title": "Youtube Customiser",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.bundle.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "http://www.youtube.com/*",
        "https://www.youtube.com/*"
      ],
      "js": [
        "contentScript.bundle.js"
      ]
    }
  ],
  "icons": {
    "22": "img/icon-22.png",
    "48": "img/icon-48.png",
    "128": "img/icon-128.png"
  },
  "permissions": [
    "storage"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self';"
}