Not hard to reverse engineer it. Mine uses a straight shank that it held in a chuck in the tailstock. The die holder itself is just a round pocket milled in the ends to fit the die closely, and there are set screws on the perimeter to secure the die.
Even though I made one, I find it just as convenient to use the manual die wrench and pressure from the tailstock to start it straight.
Here is my DIY Die holder in action. Have yet to make Die Holder for longer studs.Meanwhile existing die holder serves my requirement. I have DIY M3 M4 M5 M6 M8 die holders.Die holders are surplus from left overs. You will need a double action ratchet spanner for forward n reverse actions. I use machine spiral taps and its all the way forward till dead end and reverse to remove die.