Examine source code of WhatsApp Audio Boost

{
  "manifest_version": 2,
  "name": "WhatsApp Audio Boost",
  "version": "1.0.0",
  "icons": {
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://web.whatsapp.com/"
      ],
      "css": [
        "style.css"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e8c65bb6-e080-4545-b3b8-1ab3be422de0}"
    }
  }
}