Apparently it's a 32-socket system with Xeon Platinum 8180s in each socket. There's an article from Anandtech[0] in response to the blog post:

[0]: https://www.anandtech.com/show/13522/896-xeon-cores-in-one-p...

Skylake-SP will do glueless UPI to 224 cores (8x28). HP SuperDome Flex scales up to 32 sockets (896 processors) using a custom interconnect based on SGI’s NUMAlink.

That's what the article is about. It has a screenshot of one with 1792 logical cores.