I believe its FET switching. But its just the mechanism, not the buffering.
I'm sure when they wont claim it to be true bypass if it isnt.
Actually, we can all get true bypass from FET switching fxs if the effect manufacturers dont worry so much about cost all the time.
With a few simple changes to boss fet switchin you can actually get true bypass without drilling a hole to jam that shiny 3pdt footswitch in...