Does the Vector Math Normalize operation use the second input? The Vector Math node has an operation called Normalize.  I have always presumed that this is a monadic operator which ignores the second input and returns a unit vector in the direction of the input vector.  This is also what poor said in this answer.

However, I was recently reading the manual and noticed that it says:


  Normalize
  Normalizing input 1 and 2.


Which is super-duper unhelpful.  I have never known of a binary "normalize" operation (and couldn't find one in a quick Google search), so I don't know what "Normalizing input 1 and 2" means.

So what is going on here?  Does it use the second input, if so how?  Or is the manual just plain wrong?
Input 2 is not used, manual is wrong, I guess. Links to the source code for the node are below, you can clearly see input 2 is never called when in normalize mode. 

SVM: https://developer.blender.org/diffusion/B/browse/master/intern/cycles/kernel/svm/svm_math_util.h

OSL: https://developer.blender.org/diffusion/B/browse/master/intern/cycles/kernel/shaders/node_vector_math.osl