Package: xserver-xorg-core
Version: 2:1.20.4-1
Severity: normal
# ps aux|grep Xorg
root 582 0.3 0.8 340884 50468 tty7 Ssl+ Jun01 82:02 /usr/lib/xorg/Xorg -nolisten tcp -auth /var/run/sddm/{f66ea786-13c9-4499-95f6-f7bdce850668} -background none -noreset -displayfd 17 -seat seat0 vt7
root 1854 0.0 0.0 6076 892 pts/3 S+ 08:39 0:00 grep Xorg
# grep /root /proc/582/maps
7f628cb07000-7f628cc48000 rw-s 00000000 00:15 1030181 /root/.cache/mesa_shader_cache/index (deleted)
7f628dab7000-7f628dbf8000 rw-s 00000000 00:15 1030181 /root/.cache/mesa_shader_cache/index (deleted)
Xorg when run as a daemon from sddm should not touch any files under /root.
As an aside the system has only had one user login and that user was not root.