Horizon Forbidden West contains a hidden collectible sequence — the Black Box flight recorders from ancient aircraft — that culminates in a final transmission from the aircraft’s pilot moments before impact. Most Black Boxes are contextual flavour. The final one, found in the Burning Shores DLC, contains a message from someone who had access to the Zero Dawn project files and knew what GAIA was building.
The message is addressed to a person not named anywhere in the main series — a friend of the pilot who, the message implies, chose not to enter a Cradle vault when offered. The pilot is recording a goodbye. The friend made a choice that the pilot found incomprehensible, and the recording ends with the pilot’s attempt to understand it.
Guerrilla built a complete story of Zero Dawn-era human decision-making — specifically the choice to refuse the only offered survival — into an aircraft Black Box collectible accessible only in paid DLC. The friend’s choice is never explained. The pilot’s voice is the only testimony.

This is why I always check every corner. You never know what’s been left for the observant player.
The environmental storytelling in this game is on another level. Thanks for documenting it so clearly.