Orbot allows you to route specific apps through proxy.orb . Want your browser, email client, or even a crypto wallet to hide its IP address? Toggle it in Orbot’s “App VPN Mode.” The app will send traffic to proxy.orb , not directly to the internet.
Beyond the consumer service, "ORB proxy" has specific meanings in cybersecurity and software architecture: ProxyOrb: Free Web Site Proxy & Online Proxy Browser