Can anyone point me towards a resource regarding the stock intake design and associated plenum additions?

It seems to me that Nissan engineers added several small plenum/surge areas in the stock intake pipe before the air box. What was the reason for this?
Surely the air filter element would dissipate any intake pulse shockwave before it reached those additional areas? I can't see that those engineers would have added anything to the intake
that didn't serve some function. Are they purely additional plastic pieces that serve dress up/protection for other areas and do not contribute to the over all volume of the intake runner?
Perhaps this is to facilitate a more static air charge volume before the airbox?

I am really trying to understand the design of the stock intake. I am not planning on changing it anytime soon, just understand the theory behind such a design.

Why would you want a static amount of air? It then takes more power to move it or it cannot enter the engine. Already stimulated to be moving (hopefully IN) is better.

Again for same reason or close, the air filter does NOT stop all shockwaves, to do so means it would have to have resistance and we all know resistance in an airbox is counterproductive to power creation.

Air MUST move to get TO the airbox, therefore it can make noise, the pockets stop some of that. More to stop the resonation that echoes back up the intake tract (including before airbox) when the throttle is wide open at very low rpm. Test the idea, remove the inlet duct and then full throttle at low rpm and listen to the racket.............

It may be helpful to think of the pockets as wave dampers rather than air flow dampers. Sonic pressure wave flow and physical airflow are two different things, the physical airflow cannot ever 100% equal the sonic wave action, only partly at best. At that the air then becomes a working fluid for the sonic waves to pass back and forth in as a medium. They pass rather easily through an air filter if it flows enough to make good power.