Examine source code of Intentional YouTube

{
  "manifest_version": 2,
  "name": "Intentional YouTube",
  "version": "1.3",
  "description": "Use YouTube more intentionally, and avoid suggest content",
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*",
        "*://*.youtube-nocookie.com/*"
      ],
      "js": [
        "intentional-youtube.js"
      ],
      "run_at": "document_end"
    }
  ]
}