LookVector from ViewMatrix?

[Halsafar]

// get the look vector of the camera from the view matrix
Vector3f vLookVector;
m_mxView.LookVector(&vLookVector);

// calculate the center of the sphere
m_frusSphere.Center() = m_vCameraPosition + (vLookVector * (fViewLen * 0.5f) + m_fNearPlane);


I do not understand what this piece of code is looking for.
What exactly would a look vector be?

Would it be the position of the Player minus the position of the Camera
vPlayerPos - vCameraEye = vForward