Examine source code of Basic Tab Transfer

{
  "manifest_version": 3,
  "name": "BasicTabTransfer",
  "version": "1.0",
  "description": "Moves tabs between browsers with some copy-paste involved.",
  "permissions": [
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8c2d4426-edcf-4142-bf18-e468553c370d}"
    }
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/border-48.png",
      "48": "icons/border-48.png",
      "128": "icons/border-48.png"
    }
  }
}