This seems like the most likely explanation.

The “memory palace” (AKA method of loci) is a plausible inspiration for someone with a non-technical background, and there’s evidence that it’s closer to how the brain actually indexes memories natively. (Although my understanding is that it bootstraps the hippocampus’s hard-wired ability to remember the layout of physical locations—I don’t know that an LLM would have a similar ability out of the box.)