chromium/chrome/test/data/extensions/api_test/runtime/send_message/manifest.json

{
  "name": "chrome.runtime.sendMessage test",
  "version": "0.1",
  "manifest_version": 3,
  "description": "end-to-end browser test for chrome.runtime.sendMessage API",
  "background": {
    "service_worker": "worker.js"
  }
}