Actually, it was a "requirement" for games even before. It was and is in the quality guidelines.
https://itch.io/docs/creators/quality-guidelines#avoid-uploading-excessive-amoun...
If your project involves automatic or AI generation, make sure it’s clearly stated in your project description and that it adds substantial value to the user experience.
Though one can misread it to mean live generated AI stuff. There are games that do that. But in context it talks about AI content, such as images.
But in many cases, it was not necessary to bother either way. The usage of AI in games is often very blatantly obvious. Problematic are only the cases where the developer is activly lying or hiding the AI usage. And as has been discussed above, the usage of some AI generated code is not the same as AI generated images and story, so most people do not even think about this, when talking about "AI", in my opinion, because code != content.
While some developers did use the tagging system to state their usage of AI, there was no commonly agreed upon tag for that or the reverse.
The new feature adds the capabilities to give the information in the meta section and generate a standard tag and anti-tag and even sub-tags and hopefully more anti-subtags. And as soon, as the AI info is given in the actual information box on the project page, devs need no longer worry about that "clearly stated in your project description". (The meta info "tag" is currently is not shown. If you see an ai tag, it was manually added by the dev, not by the system. You do can search by that tag, but you do not see the ai meta info on the project page, like you do see engine info or session length and such)
With the current filtering options, a no-ai tag is also very handy, although only to be trusted for assets after the grace period, because the AI info is strictly enforced for assets due to legal ambiguties. Assets are meant to be used in other projects after all.
I do hope there will be a no-ai-content tag to exclude the code usage, because I suspect there are many developers that use ai tools for their code and most people that want to browse for "no-ai" would not mind ai code, but only ai story, images and voices.