chromium/chrome/test/data/extensions/api_test/scripting/css_injection/manifest.json

{
  "name": "Scripting API Test",
  "manifest_version": 3,
  "version": "0.1",
  "permissions": ["scripting", "tabs", "webNavigation"],
  "background": {"service_worker": "worker.js"},
  "host_permissions": [
    "http://example.com/*",
    "http://subframes.example/*",
    "http://b.com/*"
  ]
}