Without this, started qrexec-daemon would not have access to GUI, especially can't display Qubes RPC confirmation dialogs.
@@ -4,6 +4,7 @@ After=qubes-netvm.service
[Service]
Type=oneshot
+Environment=DISPLAY=:0
ExecStart=/usr/bin/qvm-start --no-guid %i
Group=qubes
RemainAfterExit=yes