I think that was because the max cable length in the USB 1.0 spec is 3 meters. The fairly short captive keyboard cable plus extension was in spec, but using th

I think that was because the max cable length in the USB 1.0 spec is 3 meters. The fairly short captive keyboard cable plus extension was in spec, but using the extension with anything else likely wouldn’t be. Hence, the weird connector to prevent you from using it to extend something else (particularly something with higher current draw)