It uses what I assume the method described in (Quintero,Eenens,Rauw,2020) does, and the older and widely used Marchenko,Moffat 1998 implemented, for example, in González, J. F., & Levato, H. 2006.
This is NOT Quintero's method, but my own experiment based on his paper. His code is not yet publicly available.
Until stated otherwise, this software is not ready to use.