chromium/chrome/test/data/extensions/api_test/webrequest_cors_preflight/manifest.json

{
  "name": "CORS preflight WebRequest",
  "description": "Test extension for webRequest api in extraHeaders mode for CORS preflight request",
  "manifest_version": 2,
  "permissions": [ "webRequest", "http://127.0.0.1/*", "http://cors.test/*" ],
  "version": "0.1",
  "background": {
    "scripts": ["background.js"],
    "persistent": true
  }
}