XDarwin

XDarwin refers to an implementation of the X Window System for the Darwin operating system, which is the core of macOS. It allows for the running of graphical applications on systems that use the X Window System, which is commonly used in Unix and Unix-like operating systems. XDarwin was part of the process of bringing the X11 environment to Mac OS X (now macOS), enabling users to run X11 applications alongside native Mac applications.