As far as I know, it's not that complicated really. Each pickup has a state variable filter, so there's a filter type switch (bandpass, highpass, lowpass, notch, although I'm not certain of the last), frequency, Q, filtered level and direct level for each pickup, which you can see as groups of 5 knobs. The other knobs are probably pickup selector switches, master volumes and controls for the quad.
Michael Delacerda had a bass that had a very similar setup minus the quad that ended up in the hands of Fred Hammon known as the Supreme Being. There was a thread about it on the old Dudepit where he went over all the controls in detail. Apparently with the filters swept all the way down, that bass can rearrange organs.
Nice to see you here, Rick!