chromium/chrome/test/data/extensions/api_test/service_worker/messaging/connect_external/initiator/manifest.json

{
  "name": "SW extension: runtime.connect initiator extension",
  "version": "0.1",
  "manifest_version": 2,
  "description": "Tests external port connection to another extension",
  "background": {"service_worker": "service_worker_background.js"}
}