Interface type question

Many programs like DVDInfoPro refer “Connection Interface” for every optical drive, and it has the value SCSI or ATAPI (IDE in some other programs). I also found this enumeration:
enum Interface {

and I want to ask where is this enumeration used. I checked inquiry, checked page 2A but nothing found about interface. Only feature 001h is using something like this enumeration but there the enumeration is different.