CustomFedoraLiveISO sysroot login

I’m trying to make a custom ISO for Fedora, but the instructions aren’t working.

You will now customize the rootfs by booting it in a systemd-nspawn container 
Any changes you make here will be present in the final generated ISO image 
Login as user 'liveuser' (no password), then run 'sudo su' to become root 
To exit the container, press '<ctrl>' + ']' three times in quick succession 

github link

CustomFedoraLiveISO

liveuser and blank password isn’t working. Password might be what Fedora ISO ships with which I’m unsure what’s the default password.