At the end of January, photos that appeared on the NeoGAF forum
gave us a first idea of the ports that the Xbox Series X will offer. There is notably a SPDIF port, two USB type A ports, an ethernet port, an HDMI port and the power supply . But also a mysterious rectangular port, initially described as a diagnostic port, which has aroused the curiosity of Internet users ever since. Meanwhile, site reporter Thurott Brad Sams
has conducted the investigation. And it seems that this rectangular port has really nothing to do with the diagnosis.
This port is for adding additional storage, according to people familiar with the subject, which allows the Xbox Series X to play the increased weight of games, as explains Brad Sams in his article.
He adds that he does not yet know what technology Microsoft uses. He nevertheless claims that the presence of an SSD inside, requires a fast storage system, including for memory expansion.
Brad noted that behind the USB ports could be used for expansion and therefore this mysterious port is dedicated to expanding storage with high speed hardware.