This kind of thing came up from time to time in the years before LLMs too. Agents would start with something based on English and optimize it until it became unintelligible to researchers. That was often something the researchers would shut down because they needed to be able to understand the comms.

They're messaging each other by jamming strings in a constrained (unauthorised) side channel. Hence the lack of spaces. Unclear how much else of the weirdness is just from those constraints