There is a lot of verilog out there, it's pretty feasible that they had AI assistance writing more to design their chip.

It doesn't have to be revolutionary, it could just be AI-assisted design and lined up well enough with their operations for a custom ASIC to be worth it.

Also there's some much boilerplate around everything. Writing a testbench with codex is extremely feasible. This is the kind of verifiable feedback loop the agents shine at.