As per bard or chat-gpt
The NetrServerReqChallenge() API is declared in the lm.h header file. This header file is part of the Windows SDK and can be found in the Include directory of the Windows installation directory.
The NetrServerReqChallenge() API is used to request a challenge from a server. The challenge is a random number that is used to authenticate the client to the server.
To use the NetrServerReqChallenge() API, you need to include the lm.h header file in your code. You also need to link your code with the netapi32.lib library.
Its not true, failed to find NetrServerReqChallenge() API in any of the header in the VS2022 / 2013 SDK.
Not able to find any WIN32 header file where NetrServerReqChallenge (Opnum 4)