Examine source code of Calculator

{
  "manifest_version": 3,
  "name": "Calculator",
  "version": "1.0",
  "description": "A basic popup calculator.",
  "action": {
    "default_popup": "popup.html",
    "default_title": "Calculator"
  },
  "permissions": [],
  "icons": {
    "128": "images/icon.png"
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self';"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "axy72h2j@1j9ez3.app"
    }
  }
}