Images of the Xbox Series X console leaked online a few weeks ago, showing off a few familiar ports on the back of the device. One connection in particular left analysts scratching their heads, with some speculating that it was a debug unit-exclusive port. The team at Thurrott now reports that it’s for expandable storage, citing “people familiar with [Microsoft’s] plans.”

The next Microsoft console will simply be called Xbox, but there are multiple versions on the way. One such version is the Xbox Series X, and it’s expected to place an emphasis on 4K, and even 8K, resolutions. That means sizable game installations, which could be even bigger than Red Dead Redemption 2’s roughly 100 GB footprint. Expandable storage would be a big benefit to consumers, who have been stuck with slower USB-based solutions or the prospect of cracking the case on their consoles to swap parts on their own.

Both the PlayStation 5 and the next Xbox will include solid-state storage, which should significantly speed up load times. But, Microsoft’s rhetoric goes a bit further, claiming that “the Xbox Series X GPU and our next-generation SSD will virtually eliminate load times and bring players into their gaming worlds faster than ever before.” Thurrot speculates that the little rectangular slot on the back of the next-gen Xbox could offer room for increased storage with CompactFlash Express (CFexpress) cards. Depending on the type of CFexpress, transfer rates could be well in excess of 1 GB per second.

CFexpress cards offer fast read and write speeds, but can be pretty pricey. (SanDisk currently sells a 256 GB CFexpress card for $399.99 and a 512 GB card for $599.99. Those cards offer read and write speeds of 1.7 GB/s and 1.4 GB/s, respectively.) But as Thurrott speculates, Microsoft may be anticipating price drops on CFexpress cards over the next decade, making upgrading the next Xbox with external storage more reasonable.

Expect more information about Microsoft’s next Xbox to come out of this year’s E3 in Los Angeles. The PlayStation 5, meanwhile, will be absent, as Sony won’t be attending the show for the second year in a row.