chromium/chrome/test/data/extensions/api_test/bindings/externally_connectable_everywhere/manifest.json

{
  "name": "Externally Connectable Everywhere",
  "description": "An extension that is externally connectable everywhere.",
  "version": "0.1.1",
  "manifest_version": 2,
  "externally_connectable": {
    "matches": ["*://127.0.0.1:*/*"]
  }
}