XScreenSaver is the standard screen saver collection shipped on most Linux and Unix systems running the X11 Window System, since its first release in 1992.
On X11 systems, XScreenSaver is two things: it is both a large collection of screen savers; and it is also the framework for blanking and locking the screen.
On macOS systems, these screen savers work with the usual macOS screen saving framework (X11 is not required).
On iOS devices, it is an application that lets you run each of the demo modes manually.
On Android, the savers work as both screen savers and as live wallpapers.
XScreenSaver celebrated its thirtieth anniversary in 2022!
"You've dosed your monkey, haven't you?"