There have been a couple of references that lead me to think it’s more than just the LED.
From the product listing (emphasis mine): “The probe is an active probe, and when contacted to ground, communicates its position to Carbide Motion.”
And from a post that @RichCournoyer made a while ago when he was testing it: “I have seen the board [in the touch probe] and there are about 10 chips on board. Really. I was surprised too”