The HP 789530-001 removable hard drive frame/carrier is a replacement assembly for a removable drive setup. The listing identifies it as an SAS/SATA frame/carrier assembly, giving its intended drive interface family.
The same listing specifies use as an HP 3.5-inch removable SATA HDD frame/carrier. It is therefore described for a removable 3.5-inch SATA hard-drive frame application. The part number and assembly name identify this particular HP spare part, so the description stays focused on that frame/carrier rather than on a drive itself.
This is a mounting and carrier component for the documented removable hard-drive arrangement; no drive capacity or additional included parts are specified.