Examine source code of Watch on Nebula

{
  "manifest_version": 2,
  "name": "Watch on Nebula",
  "description": "Prompts you to watch a YouTube video on Nebula instead, if available.",
  "version": "0.0.2",
  "icons": {
    "64": "icons/watchonnebula_x64.png"
  },
  "background": {
    "scripts": [
      "polyfill/browser-polyfill.min.js",
      "scripts/background_script.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "polyfill/browser-polyfill.min.js",
        "scripts/content_script.js"
      ],
      "css": [
        "css/popup-style.css"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "https://standard.tv/"
  ]
}