Linkwitz Transform: Attenuator or Booster?

Is the Linkwitz Transform circuit of ESP Project 71 a bass booster or a mid-range attenuator?

1. If it's a bass booster, I can plug it in after the active-crossover where only the subwoofer signal is left.

2. If it's a mid-range + hi-freq attenuator then it will have to be plugged in before the crossover since it will need to work on the full signal.

Any help is appreciated.