I don't know if even they know that they're looking for with the question as they marked it as experimental and optional but the explanation perhaps gives some hint:
"Optional: attach a coding agent session you're particularly proud of.
This is an experimental question for the Spring 2026 batch to give people a chance to show off their skills with AI coding tools."
Maybe they're hoping to gain some signal around a correlation between good AI coding skills and future company success?
I don't know if even they know that they're looking for with the question as they marked it as experimental and optional but the explanation perhaps gives some hint:
"Optional: attach a coding agent session you're particularly proud of. This is an experimental question for the Spring 2026 batch to give people a chance to show off their skills with AI coding tools."
Maybe they're hoping to gain some signal around a correlation between good AI coding skills and future company success?