chromium/chrome/test/data/extensions/api_test/browser_action/popup_with_fencedframe/manifest.json

{
  "name": "Popup with fenced frame",
  "version": "0.1",
  "manifest_version": 2,
  "description": "Test a browser action popup with a fenced frame",
  "browser_action": {
    "default_popup": "popup.html"
  }
}