chrome-extensions-samples/functional-samples/sample.page-redder/manifest.json

{
  "name": "Page Redder",
  "action": {},
  "manifest_version": 3,
  "version": "0.1",
  "description": "Turns the page red when you click the icon",
  "permissions": ["activeTab", "scripting"],
  "background": {
    "service_worker": "service-worker.js"
  }
}