Concerning the name "Yserver": be aware that there also existed (the implementation is still available for download) the "Y Window System"

> https://www.y-windows.org/

by Mark Thomas as an experimental sucessor of the "X Window System" (its development has been cancelled for a long time; the latest release that is available on this website is from 2004).

The German Wikipedia still mentions the "Y Window System":

> https://de.wikipedia.org/w/index.php?title=X_Window_System&o...