Examine source code of Youtube Music Notifier

{
  "manifest_version": 3,
  "name": "ytm-notifier",
  "version": "0.1",
  "browser_specific_settings": {
    "gecko": {
      "id": "@ytm-notifier.giorgiodg",
      "data_collection_permissions": {
        "none": {
          "description": "This extension does not collect or transmit any personal data."
        },
        "required": [
          "none"
        ]
      }
    }
  },
  "description": "Native macOS notifications for new songs on YouTube Music",
  "permissions": [
    "notifications",
    "activeTab",
    "tabs"
  ],
  "host_permissions": [
    "https://music.youtube.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://music.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  }
}