Examine source code of Transpose / Speed / Reverb - Shifter

{
  "manifest_version": 2,
  "name": "Transpose / Speed / Reverb Shifter",
  "version": "3.5.5",
  "description": "High-quality transpose, speed and reverb controls for YouTube, Spotify and Apple Music. Default and Time Correction Modes.",
  "browser_specific_settings": {
    "gecko": {
      "id": "transpose-shifter-studio@LmExtensions",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "activeTab",
    "storage",
    "*://*.youtube.com/*",
    "*://open.spotify.com/*",
    "*://*.soundcloud.com/*",
    "*://music.apple.com/*",
    "*://*.amazon.com/*",
    "*://*.amazon.co.uk/*",
    "*://*.amazon.de/*",
    "*://*.amazon.fr/*",
    "*://*.amazon.es/*",
    "*://*.amazon.it/*",
    "*://*.amazon.ca/*",
    "*://*.amazon.co.jp/*",
    "*://*.amazon.com.au/*"
  ],
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_action": {
    "default_icon": "icons/icon48.png",
    "default_popup": "popup.html",
    "default_title": "Transpose / Speed / Reverb Shifter"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*",
        "*://open.spotify.com/*",
        "*://*.soundcloud.com/*",
        "*://music.apple.com/*",
        "*://*.amazon.com/*",
        "*://*.amazon.co.uk/*",
        "*://*.amazon.de/*",
        "*://*.amazon.fr/*",
        "*://*.amazon.es/*",
        "*://*.amazon.it/*",
        "*://*.amazon.ca/*",
        "*://*.amazon.co.jp/*",
        "*://*.amazon.com.au/*"
      ],
      "js": [
        "loader.js",
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    "worklet.js",
    "inject.js"
  ],
  "content_security_policy": "script-src 'self' 'wasm-eval' 'unsafe-eval'; object-src 'self';"
}