What are these 3 keys in the executive section of the registry in windows

In a windows internals book i read a sample of on google mentioned the following section of the registry

HKLM\System\CurrentControlSet\Control\Session Manager\Executive
And in that section it brings up AdditionCriticalWorkerThreads,AdditionDelayedWorkerThreads and HypercriticalWorkerThreads

Does anyone that have a server have any knowledge on these 3 keys

AdditionCriticalWorkerThreads
AdditionDelayedWorkerThreads HypercriticalWorkerThreads

Because i cant find a solid piece of info on hypercriticalworkerthreads but as for

AdditionCriticalWorkerThreads
AdditionDelayedWorkerThreads

I try to dig deeper and get solid info but i get confused

https://books.google.com/books?id=w65CAwAAQBAJ&pg=PT337&lpg=PT337&dq=HKLM%5CSystem%5CCurrentControlSet%5CControl%5CSession+Manager%5CExecutive​&source=bl&ots=4Xl4q3SkUs&sig=l8WpefggKXh4bmEfKXpizQTYahk&hl=en&sa=X&ved=2ahUKEwjK8r-bjenaAhWNn4MKHSD4CcU4ChDoATAAegQICRAB#v=onepage&q=HKLM%5CSystem%5CCurrentControlSet%5CControl%5CSession%20Manager%5CExecutiv​e&f=false