Sram is saving weight, making a couple of standards to one and making their 1X drivetrains look cleaner and keeping it Sram. Spiderless chainrings been around for some time now but not until now Sram starts with it. All the way from 26t to 40t, bigger than other produce.
2 types, one for GXP and one for BB30. Offset differences. But for XX1, X01 and X1. Will fit X.0 and X.9 crankset too but not sure the chainline is as good as with the 1X cranksets. More info here on Bikerumor