Nice find. A quick way to get that info, without reading through so many lines is this:
$ ioreg |egrep 'IOUSBAttachedSCSI|IOUSBDevice|IOUSBMassStorageClass'
It will only list the lines related to those USB entries, in my case:
| | | +-o HP HD Webcam@1d170000 <class IOUSBDevice, id 0x10000026f, registered, matched, active, busy 0 (72 ms), retain 12>
| | | | +-o IOUSBDeviceUserClientV2 <class IOUSBDeviceUserClientV2, id 0x100000398, !registered, !matched, active, busy 0, retain 7>
| | | +-o BCM20702A0@1d132000 <class IOUSBDevice, id 0x100000273, registered, matched, active, busy 0 (746 ms), retain 14>
| | | +-o Apple Keyboard@1d134200 <class IOUSBDevice, id 0x100000509, registered, matched, active, busy 0 (352 ms), retain 12>
| | | +-o Firebird USB Flash Drive@1d140000 <class IOUSBDevice, id 0x100000631, registered, matched, active, busy 0 (463 ms), retain 9>
| | | +-o IOUSBMassStorageClass <class IOUSBMassStorageClass, id 0x100000637, registered, matched, active, busy 0 (240 ms), retain 9>