Annoyed of “universal” drill holders, which always left behind few spare drills, because they does not fit in? Not anymore, build you own modular drill holder. Part by part, then plug them together. Or split. It is really up to you. New drill? No problem, just print one more module and place it in between as you need.
FreeCad model is parametric model. See “cfg” part.
The author hasn't provided the model origin yet.