Solved Creating post-shutdown script of kernel output

After a user session I view kernel output flash on my display monitor. Is there a way to create a script report of this kernel output? Or should I try to find log reports in the /var directories?

I have used the reports from: /var/log/Xorg.0.log and these have been useful.
Is this maybe a matter of terminology? The description sounds like the screen flashing into and out of virtual console while X reinitializes. Those screens can be viewed by Ctrl-Alt-F1, Alt-F2, Alt-F3, and so on. The exact modifier keys might vary or might not work at all, depends on the setup.

Okay it might be the terms I have used. The last 15 seconds after a user-session, when the system is preparing for full shutdown, there appears a list of small warnings, which I presume are to be given a notice if not full remedy.

I have been able to slowly tweak my system hardware into better performance when I pay attention to warnings, let alone full blown error messages.

The location of log files are sometimes very helpful. In addition, I have learned to run current script logs for user sessions to provide additional hints on warnings and other areas that should be attended to.

The most common one is: ...something like..iCCP warning: known incorrect sRGB profile...another refers to libGL.
But before I can react the system is already to shutdown.
Ah, ok. I was off the mark.

Messages you describe likely go to the virtual console screen X was started from. Some might also be logged via syslog to /var/log/somefile. Maybe you got an option to go to single-user mode instead of full shutdown. Time to read the screen.

Okay, thanks for the insight on this one.

So based on reading the virtual console screen, I guess this issue is solved.