It was described in the book Dames de Paulovits and in the Classified Encyclopedia of Chess Variants (2007).
The new files hold respectively a pasha and a general with a pawn in front.
The pasha jumps one or two squares in all eight orthogonal and diagonal directions and is thus a bit like a very short queen which can leap over other pieces.
The general has the moves of a mann and a camel, that is it can jump to the eight adjacent squares or to the opposite corner of a 2×4 rectangle.
Pawns can make an initial three-step move and a king castles by moving either two squares king-side or four squares queen-side.