John, I'm sure Darryl will be along shortly.
Gliders are not required to have a transponder or ADS-B Out.
You are not required to add Out GPS data to the Trig unless you chose to. But if you do it must meet the standards.
FAA has recently reworded the language that allows "Experimental" kit built aircraft to install non TSO'd ADSB out systems as long as they meet the same standards. I'm not sure if that applies to experimental gliders.

We have Trig21 on some of our gliders, inside the Mode C Veil, we are not planning to add GPS to the Trig.
BillT