I'm not saying I know I'm right, but I think it is highly suggestive that the light in the centre is labelled 'df1'. 'WP ON' could mean "write protect". Side A and B are obvious if I follow my opening assumption. My bet is it plugs into a floppy drive external connector and with a piece of software listening to it, drive accesses could be analysed perhaps for software debugging maybe? Is there a switch on it for toggling write protection? Could that be done in software?
