chromium/chrome/test/data/extensions/ntp_override/manifest.json

{
  "name": "New tab override test",
  "version": "1",
  "manifest_version": 3,
  "description": "Test successfull uninstall of externally loaded extension which overrides ntp url.",
  "chrome_url_overrides": {
    "newtab": "override.html"
 },
  "permissions": [
    "tabs"
  ]
}