Update:

>> A bit of secrecy for this OpenPower hardware.. ;-)

> Yes, unfortunately, the PowerPi SIG operates in complete confidentiality.

Statement on PowerPi by the Libre-SOC project lead and Technical Director of RED Semiconductor:

"Toshaan Bharvani started the PowerPI initiative, but it was soon taken over by naive people believing that you can get a 5 watt system to do 4-core 3 ghz 7 nm with 128-bit-wide DDR3/4/5 memory and multiple lanes of PCIe and multiple lanes of OpenCAPI in under a budget of USD 10 million, when 7nm Mask Charges are $10 million on their own."
https://lists.debian.org/debian-powerpc/2023/03/msg00014.html

I'm not really sure what to make of this.