At WWDC 2024, Apple announced Private Cloud Compute, a service to handle complex AI requests in a secure context. An 

 describes the server hardware in several paragraphs:

The root of trust for Private Cloud Compute is our compute node: custom-built server hardware that brings the power and security of Apple silicon to the data center, with the same hardware security technologies used in iPhone, including the 

We supplement the built-in protections of Apple silicon with a hardened supply chain for PCC hardware, so that performing a hardware attack at scale would be both prohibitively expensive and likely to be discovered.

Private Cloud Compute hardware security starts at manufacturing, where we inventory and perform high-resolution imaging of the components of the PCC node before each server is sealed and its tamper switch is activated. When they arrive in the data center, we perform extensive revalidation before the servers are allowed to be provisioned for PCC.

After the service launches, will this server hardware be substantially similar to any existing Mac (Pro, Studio, mini, etc.)?

 Modifications to the case like a tamper switch and rack-mounting bracket are still considered similar. A redesigned logic board is not.

 on Dec 1st, 2024 if no conclusive indicators are given by Apple or a "blessed" secondary source like Joanna Stern, John Gruber, MKBHD or iJustine.