Examine source code of Invidious Playlist Timer

{
  "manifest_version": 2,
  "name": "Invidious Playlist Timer",
  "version": "0.1.0",
  "description": "Displays the total duration of video playlists on Invidious instances, making it easier to manage your viewing time",
  "homepage_url": "https://github.com/rsapkf/inviduration",
  "content_scripts": [
    {
      "matches": [
        "*://invidious.snopyta.org/playlist?list=*",
        "*://invidious.kavin.rocks/playlist?list=*",
        "*://*.invidious.xyz/playlist?list=*",
        "*://*.yewtu.be/playlist?list=*",
        "*://*.invidious.tube/playlist?list=*"
      ],
      "js": [
        "content-script-invidious.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{18b83609-b437-4292-aa18-0078eb5f44e6}"
    }
  }
}