KDE Live can be installed without creating a regular user, only root. All you need to do is to not create a regular user in anaconda (only root), and then not create a regular user in the first boot utility (just click Finish). In SSDM, it is then possible to log in using the root account (not a good idea in general, to be sure).

Is this intentional, or a bug? Should KDE require creating a regular user, similarly to Workstation?