Homo naledi remains deep in an obscure cave system: “What today’s cavers can do is not a good guide to what a smaller species, better adapted and practiced at climbing, might have done.”

https://johnhawks.net/weblog/how-homo-naledi-got-into-the-dinaledi-chamber/

One may speculate that for them it was a very secure place to visit or live in.

There are probably other similar spaces we would need to explore via bots.