Unfortunately the documentation for rotations in Wired4 is a bit lacking.
Rotations in general can be decomposed into three consecutive rotations about the primary axes.
R_x = R1R2R3
In Wired, the choice was made to rotate by an angle omega about the z axis, followed by a rotation by theta about the new x axis, followed by a rotation about phi around the y axis.
The ultimate reference, as usual, is the code, in this case for Matrix3D
In Wired4, the choice of rotation is
Unknown macro: {latex}
(x^2)