fedora-live-kde.ks file provided for building standard kde workspace spin does not work. Despite the fact that @kde-desktop group is present, package "plasma-workspace" is not installed (not sure if it's a .ks file fault or of livecd-creator). One has to explicitly add this package in .ks file and it works.

The problem is that if .ks file is used as provided, then when booting livecdat boot:
1) /usr/bin/startkde is missing
2) /usr/share/xsessions/plasma.desktop is missing
3) after typing username and password, nothing happens because sddm windows manager is there, but there is simply no plasma session behind the login screen.

Hope it helps to those who will build it