The Legend of Mala Tokmachka

The developers describe how their game uses AI generated content like this:

Some visual assets in the game were created or refined with the assistance of generative AI, and AI tools were also used to support localization.

Required on Steam store pages since 2024. It covers content that ships in the game, on its store page or in its marketing — Valve does not require a disclosure for AI tools used during development, so this says nothing either way about how the game was made. Check it on Steam.