Examine source code of YoutubeFeed

{
  "description": "Add a feed to Youtube in the style of Twitter. You can choose to follow people and their watched videos will appear in your feed",
  "manifest_version": 2,
  "name": "YoutubeFeed",
  "version": "1.0",
  "homepage_url": "https://github.com/TheGreatRambler/YoutubeFeed",
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  }
}