It was developed by a TSN regular. It appears to fool the MAP sensor into thinking the boost is lower than it is, making Trionic increase boost slightly. It is viewed with great suspicion by many people on TSN and elsewhere.
The first question in their FAQ indicates that it will have no effect on the boost gauge. However, the boost gauge on T5 systems is a purely mechanical device driven directly from manifold pressure. If boost increases, I would expect to see it on the gauge.
By raising the overboost fuel cutoff level, it therefore significantly reduces the protection offered.
It's not a route I would recommend myself for reasons I've expanded on many times before. If you want a safe, reliable increase in performance IMO the correct way to do so is via software control, not by any sort of gadget or add on that provides misleading information to Trionic.