The fast, stable, and always free Linux VNC client

One of Remmina’s many features is a VNC client in the connection manager with many tunable options to get you connected just how you want

Virtual Network Computing - Wikipedia

Virtual Network Computing (VNC) is a graphical desktop-sharing system that uses the Remote Frame Buffer protocol (RFB) to remotely control another computer. It transmits the keyboard and mouse input from one computer to another, relaying the graphical-screen updates, over a network.