I wonder if the timing of this, coming so soon after the Musk/Anthropic data center deal is just coincidence or not?

From Karpathy's various interviews I get the impression that he wants to leave the door open to working for Musk again at some point, perhaps on TeslaBot.

With Musk for now regarding Anthropic as a partner (or at least an enemy of his enemy), that seems to mean that Karpathy joining them is less likely to anger Musk than might otherwise have been the case. Who knows, maybe Karpathy was involved in brokering this data center deal?