Strangest USB Cable ever?

[SC68Cal]

Ok, someone help me identify this. It's not a standard USB extension cable, because it has a bump in the middle of the USB input. What is this for?

It came with my friend's late 2005 iBook.

 

[SMM]

Mac Keyboard extension?

 

[applemacdude]

its a proprietary apple usb extender with use only with their keyboards

 

[SC68Cal]

great. my housemate is much obliged