Commit from core2:
commit 94d52a13e7
core: adjust guid parameters when running on KDE5
On KDE5 native decoration plugin is used and requires special properties
set (instead of `_QUBES_VMNAME` etc).
Special care needs to be taken when detecting environment, because
environment variables aren't good enough - this script may be running
with cleared environment (through sudo, or from systemd). So check
properties of X11 root window.
QubesOS/qubes-issues#1784
19d9edc291