Madhearts

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

All final artwork is created by our artists. AI-generated 2D placeholders are clearly labeled and will be replaced during production. Generative AI also assisted with select audio elements under our team’s direction.

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.