X11R6

X11R6 refers to a version of the X Window System, which is a software framework used to create and manage graphical user interfaces on Unix-like operating systems. Developed by the open-source community, X11 provides the underlying technology that allows different applications to display graphics and interact with users across various hardware and network configurations. Version 6 (R6) indicates a specific release that introduced improvements in performance, stability, and flexibility, enabling more consistent and customizable visual interfaces. It remains foundational in many systems, supporting the development of modern desktop environments and applications.