On a system running the K Display Manager, when is the /etc/kde4/kdm/Xreset script automatically executed?

The `Xreset` script runs *after* sessions, not when KDM itself starts; `Xsetup` or `Xstartup` scripts are executed at KDM start or before session launch.

The KDM `Xreset` script is specifically designed to perform cleanup tasks after an X session finishes. It runs post-session to revert any changes made by the session or clean up temporary files, ensuring the system is ready for the next user or session.

KDM crashing is an abnormal termination and typically doesn't trigger standard cleanup scripts like `Xreset`, which is part of the normal session lifecycle.

Restarting X or the display manager typically involves different scripts for setup or pre-session actions, not `Xreset` which is for post-session cleanup.

An X crash is an unexpected event that might prevent `Xreset` from executing cleanly, as it's intended for graceful session termination.