The image above of the Xbox Series X backside has been floating around for a couple of weeks. All the ports are self explanatory, except for the mysterious rectangular slot.
Initial reaction was this mystery slot was a debug port, specifically for prototype units, but perhaps this port has a consumer benefit. Some are speculating that this is for expandable high speed memory.
According to a poster on Thurrott.com:
Given that 1) the “debug port” on the Xbox Series X looks to be roughly 31mm x 4mm, 2) that a LinkedIn entry showed Phison’s PS5019-E19T controller being developed for or used by the Series X, 3) that Phison’s datasheet for that controller shows that it can be used in a CFExpress form factor, and that the dimensions of a Type B CFExpress card are 29.8mm x 3.8 mm… Do you think it’s possible that rather than having an internal non-replaceable NVMe-style SSD, they are using Compact Flash Express for the SSD so that you can expand in the future?Thurrott.com
So there you have it. I was hoping that this would be used for Kinect 2.0, but foiled again.