It is, and always has been.
When adding content you have a setting, “Yes — This project contains the output of Generative AI”, which is the recommended way to tag AI generated content communicated by itch.io.
Yes, about half of this pack benefited from AI (in lineart, textures, ideas, sketches, etc). Then hand-finished manually to make usable afterwards.
Tiles and NPC sizes are all based on 16x16
Enjoy!