Examine source code of ST Whatsapp

{
  "manifest_version": 3,
  "name": "ST Whatsapp",
  "version": "1.1",
  "description": "Custom Copy WhatsApp messages with just a click",
  "icons": {
    "16": "images/icon16.png",
    "32": "images/icon32.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "ST_Whatsapp"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "ST_Tred@firefoxExtension.net"
    }
  },
  "content_scripts": [
    {
      "js": [
        "script.js"
      ],
      "css": [
        "styles.css"
      ],
      "matches": [
        "*://web.whatsapp.com/*"
      ]
    }
  ]
}