It uses relays for switching the loops.
There are 2 modes:
In mode one it works like a standard bypass looper: All 3 loops can be toggled on and off.
In mode two only one loop can be turned on at a time ie: If loop B is on and you turn on loop A, loop B turns off.
The original circuit I designed used digital chips (schmitt triggers and J K flip flops) but I had some switching problems.
In the end I stripped most of the components off the board (hence all the spare holes) and used a microcontroller to do the magic.
) but yeah, bang on, I thought I'd try and keep the potential for hiss boosting down.