Examine source code of DeezyTracker

{
  "manifest_version": 2,
  "name": "DeezyTracker",
  "version": "1.2",
  "description": "Track your Deezer music to use the DeezyStatus Slack App",
  "permissions": [
    "storage",
    "activeTab",
    "https://deezy-status.vercel.app/*",
    "https://*.deezer.com/*"
  ],
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.deezer.com/*"
      ],
      "js": [
        "contentScript.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "deezytracker@deezystatus"
    }
  }
}