Examine source code of Quick GST Calculator

{
  "manifest_version": 2,
  "name": "GST Calculator Pro",
  "version": "1.0.0",
  "description": "Professional GST calculator for quick tax calculations with rates of 5%, 10%, 15%, and 20%",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_title": "GST Calculator Pro",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png",
      "128": "icons/icon-128.png"
    }
  },
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "browser_specific_settings": {
    "gecko": {
      "id": "{00e5d1f2-01b8-4a7f-a6cd-4bb340c9aca6}"
    }
  }
}