sddm-state.conf man page
state.conf — sddm display manager configuration
This file carries state configuration for the sddm display manager sddm(1).
All options are configured in the [Last] section:
Name of the session file of the last session selected. This session will be preselected when the login screen shows up. Default value is empty.
Name of last logged-in user. This username will be preselected/shown when the login screen shows up. Default value is empty.
The full documentation for sddm is available at https://github.com/sddm/sddm