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

{
  "name": "webRequest_sendMessage",
  "version": "1.0",
  "manifest_version": 2,
  "description": "Tests the SendMessageToExtension feature of declarative webRequest API.",
  "permissions": ["declarativeWebRequest", "<all_urls>"],
  "background": {
    "scripts": ["background.js"],
    "persistent": true
  }
}