/etc/enclosure_n.conf

This appears to be where the Physical enclosure disks are defined.

In my system, the following enclosures exist:

• enclosure_0.conf: The primary physical NAS drive enclosure, which can hold up to 6 disks.
• enclosure_1.conf:
• enclosure_3.conf:
• enclosure_33.conf: A generic enclosure ID for all external disks connected to the USB3 ports.

  Enclosure 0 is the physical drive enclosure, which can hold up to 6 disks.
  Enclosure 33 is a generic enclosure ID for all external disks connected to the USB3 ports.