. install a firstboot script virt-sysprep --script=/tmp/foo.sh
. run an external shell script
. run external guestfish script virt-sysprep --fish=/tmp/foo.fish
+ . rm /var/cache/apt/archives/*deb
- log files (thanks Steve Grubb)
. as well as the obvious log files, also
utmp/wtmp/btmp/tallylog and pam_faillock's data files