Internet-Security.com TCP port 9222 details

TCP port 9222 is widely used by Google Chrome/Chromium for the Chrome DevTools Protocol when launched with --remote-debugging-port=9222 (including headless mode).
Automation tools like Puppeteer and Playwright commonly connect to ws://localhost:9222/devtools/... to control an already-running browser.
Other Chromium-based browsers support the same mechanism on 9222, including Microsoft Edge (msedge --remote-debugging-port=9222), Brave, and Opera.
Electron apps often enable Chromium remote debugging on 9222 during development or troubleshooting.
Headless Chrome Docker images, such as justinribeiro/chrome-headless, expose 9222 for remote DevTools access.
Chrome on Android is frequently debugged by forwarding the device socket to desktop TCP 9222 via: adb forward tcp:9222 localabstract:chrome_devtools_remote.
The protocol here is the Chrome DevTools Protocol over HTTP (e.g., /json endpoints) and WebSocket.
Security note: attackers scan for exposed 9222 and can control the browser via DevTools (open tabs, navigate, run JS, and extract cookies/localStorage), so it should never be publicly exposed.

TCP 9222