Reusing this, it’s easy to open the file manager, whatever the template is:
#!/bin/sh
ID=`xdotool getwindowfocus`
QUBE=`xprop _QUBES_VMNAME -id $ID | cut -f 2 -d\"`
if [[ "$QUBE" == "$_QUBES_VMNAME: not found." ]]; then
exit
else
qvm-run "$QUBE" /usr/bin/xdg-open /home/user &
fi