Datasheet JTAG Adapter V1.0
https://edx-twin3.org
Description:
The Jtag adapter is either a fixed +3.3v power source within a Jtag interface adapter, or a Jtag adapter with a fixed +3.3V power source, anyway, it can be used as a simple power source, as an adapter for you probe, or both.
Schematic:

PCB Pinout: