Examine source code of Lyrics Overlay

{
  "manifest_version": 2,
  "name": "Lyrics Overlay",
  "version": "1.0.2",
  "description": "Show lyrics overlay for YouTube Music & Spotify.",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [
        "https://music.youtube.com/*",
        "https://open.spotify.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "lyrics-overlay@example.com",
      "strict_min_version": "102.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}