It's their marketing term for their HDR tech. The XDR displays are their flagship media productivity monitors. The new screens in the 14/16 inch MacBooks have "XDR" tech as well.
Just so I don't misunderstand, does that mean I need XDR or will it work with any monitor? I was very surprised to see that the original M1 only supported one external monitor so just want to confirm before I press buy.
It will of course work with other monitors, but there aren't that many high res monitors out there. The Apple display is the only 6k monitor I know of. There are a few 5k monitors and lots of 4k monitors.
There's one 8k monitor from Dell, but I don't think it's supported by macOS yet.
