Default user after installing lightdm (Raspberry Pi Imager)?

Ken Peel's icon

I installed the OS on a Pi using the Raspberry Pi Imager and thought I would try the desktop.

Using raspi-config I changed the boot preference to desktop, installed lightdm as prompted, and started VNC.

I can VNC to the Pi OK, and the desktop is displayed, but I'm prompted for a user name and password - is there a default?