To be even more leet, check out the included screensaver "Gibson". You can hack the Gibson to find the garbage file like a one of the true Hackers (TM).
KDE Plasma does not really support the X11 session anymore. It will break more and more, switch to Wayland ;) there are screensavers too I think (the concept is silly lol)
Not quite. Upon a Google, it looks like they are hacks, but Wayland doesn’t support programs (like the Xscreensaver daemon) blanking the screen and would need a standard to do so.
However, these screensavers are just individual binaries that the daemon executes, so although they won’t pop up automatically, you should still be able to run and enjoy them as fun little graphics demos.