How do i list the types of virtual disk virtualbox can use?

[amurleopard]

$ vboxmanage list hddbackends
Supported hard disk backends:

Backend 0: id='VMDK' description='VMDK' capabilities=0x0a7f extensions='vmdk (HardDisk)' properties=()
Backend 1: id='VDI' description='VDI' capabilities=0x0e77 extensions='vdi (HardDisk)' properties=()
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