Concerning the name "Yserver": be aware that there also existed (the implementation is still available for download) the "Y Window System"
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...
On general principle, I think 22 years of inactivity is perfectly reasonable for considering any software project perfectly dead.