Examine source code of YT Playback Calculator

{
  "manifest_version": 2,
  "name": "YT Playback Calculator",
  "short_name": "yt-pb-calc",
  "description": "See video duration for different playback speeds on YouTube.",
  "version": "3",
  "homepage_url": "https://github.com/kurtnettle/yt-pb-calc",
  "content_scripts": [
    {
      "run_at": "document_idle",
      "js": [
        "content-script.js"
      ],
      "matches": [
        "https://www.youtube.com/*",
        "https://m.youtube.com/*"
      ]
    }
  ],
  "icons": {
    "16": "icons/16.png",
    "48": "icons/48.png",
    "128": "icons/128.png",
    "256": "icons/256.png",
    "512": "icons/512.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{46df6f5c-f3f8-46f2-8d5d-785652118b14}"
    }
  }
}