This solver uses the excellent lrs - David Avis's implementation of Avis and Fukuda's reverse search algorithm for polyhedral vertex enumeration.
In particular, this uses an interleaved reverse search on two polyhedra, which was introduced in version 4.2 of lrs (see here).
For a description of the method see
D. Avis, G. Rosenberg, R. Savani , and B. von Stengel (2010), Enumeration of Nash Equilibria for Two-Player Games. Economic Theory 42, 9-37.
This page was created and is maintained by Rahul Savani and is kindly hosted by the LSE Maths Department courtesy of Bernhard von Stengel.