Byrg is a Blokus engine compatible with Pentobi GTP. It can play the Classic and Duo variants.
Byrg has no GUI of its own and thus cannot easily play against human opponents. It is intended for use with Pentobi's twogtp. My own patch of twogtp also works with four engines.
At the end of the game, twogtp outputs a Blokus game file, which you can open and inspect using Pentobi.
cmake .
make
See driver.sh for an example of using twogtp to orchestrate a game.