@kperryua is working hard on a "Codable 2.0", so that's what people here are alluding to - The future of serialization & deserialization APIs
While the new world may replace old Codable, perhaps we can view this pitch more like a cleanup than anything else really -- those types living in Combine are pretty out of place, and it would make sense to move them. I've definitely encountered this problem in the past when I was working more with Codable.
Since there's existing systems using Codable, I'd support this cleanup, even if we're moving towards the "2.0" future with new APIs.
Kevin likely has some opinions here as well.