jbl tlx 20

just had to repair a couple of jbl tlx 20....xovers inside where third order for tweeter and midrange

i noticed inside the x overs together with the third element of the tweeter network a bipolar capacitor of 12 mfd a 100nf bypasss capacitor

that was a first for me !!!! anybody know why ?????
what does it help to have bypass capacitor of 100nf ?????