As the company's helpful video above points out, the unit consists of a pair of TRS stereo and a pair of mono jacks. The tip and ring of each TRS jack is routed to a mono jack for you to create parallel signal paths and the Split | Meld is especially useful for any effects on your pedalboard that offer TRS input and dual mono output.
Players can now effectively use their parallel signal paths together with the Split | Meld for stereo output rather than mono. If that doesn't make any sense, you may not need it… yet. OBDE says they'll be making a video soon to illustrate various creative setups that is could be used it - and that might just spark new inspiration for players.
More info at oldbloodnoise.com