Thanks for the clarification. I am not sure what exists in term of documentation, only NVIDIA can state that authoritatively.
Orin and Grace-Hopper are targeted at different markets from what I can see. Orin is intended for the embedded market, that is, it has a sizeable number of 3rd party users, which provides good motivation to offer a technical reference manual. To my (limited) knowledge Grace-Hopper is intended for servers and currently only ships in systems sold by NVIDIA. If so, no publicly available technical manual would be needed.
The formal documentation for Grace and Grace Hopper is here. As with other products, you may also find blogs, whitepapers, GTC articles and recordings, and other assets. (Here is an example GTC item.)