Oof, I don't like that Matrix3x2 type. "It's a 3x2 matrix, but we're going to pretend it has a last column going 0/0/1 so we can get a determinant or multiply them together, but when we negate or add or subtract them it's still going to be 0/0/1."
It's the classical representation of affine transforms (translate, rotate, scale, etc) using homogeneous coordinates.