From the drawings filed as part of the application, it seems that the stand features two feet that are at either end of along pole. That pole would then have a pair of magnetic mounts the displays would attach to. There would also be space for the displays to move horizontally, too.
A joint in the middle of the stand would allow the displays to be angled inward if the user required. The whole thing could of course be replaced by two different VESA mounts or stands, but Apple thinks this route is better.
When users use multiple displays in a workspace, the displays are generally supported by multiple different individual stands or by independently-movable arms that extend from a single support point. These individual stands or arms unnecessarily take up large spaces, are often aesthetically unpleasing, overcomplicated, and have inefficient redundant mechanisms. When multiple displays are used on independent arms, they can be difficult to align in a smooth and precise way due to inconsistent counterbalancing and arm lengths. When multiple displays are used on a single support, they cannot be effectively adjusted relative to each other about a vertical axis.
There’s obviously no guarantee that we will ever see a stand like this, but one thing is certain. If Apple did sell something along these lines it would make the Pro Display XDR’s single unit stand seem cheap at $1000.