Sorry – the PAB executes off-chain code and provides services to wallet backend and nodes:
From: PAB Architecture
“The PAB executes the off-chain component of Plutus applications. It manages application requests to wallet backend and node, stores the application state and offers an HTTP API for managing application instances.”
So not quite what I was looking for … hmmm.
There is another forum post that poses similar questions:
What services go into the stack between a running Node (backend) and a User interface (frontend)?
Also, can’t edit topic title nor my previous post.