What kind of drive is Z: - an SSD; an HDD; a VM drive; a subst drive; a USB pen drive; a NAS drive; an SD card; a mounted ISO image?  Something else?
[..] represents the parent of ANY subfolder in ALL windows operating systems since Windows 1.1.  Only a drive "root" (A:, B:, C:, ... Z:) will not have a [..] parent.