You could test by ssh -X from a Linux machine, for example. But in general there is a lot of useless stuff in haikudepot now. A mix of laziness, people going “oh shiny!” and porting some lib for no reason, and too much automation of getting packages to the users without checking if they are useful.
I agree the X11 libs should be removed, and XEmacs should use translators to open its icons, just like gvim does.