The "IN" probably refers to in one of the camera modules, or some other module/HAT.
Raspberry Pis don't use any Sony chips on the SBC, Sony image sensors are on the camera modules, and since they're talking about imaging, this makes perfect sense.
Nothing about the Engadget article says to me it'll be on board the Raspberry Pi itself.
The original press releases don't say anything about incorporating it into the base Pi hardware and I don't think they would, given that it would add extra cost and most people don't need it.
Based on what? Even the linked article title says IN. Maybe they have different models, but based on all the wordings, it is very odd if it is HAT.
> Complaining about this shows ignorance.
If it is external HAT, then maybe. But until then, maybe not.
Edit: There seems to be AI kit available now, but it does not include this:
https://www.raspberrypi.com/documentation/accessories/ai-kit...