I found it hard to understand what this is. Overall summary, it's using new Linux kernel features to make Docker style containers way more efficient
It allows you to compose a bunch of filesystems into one layered stack of read only, at a mount point. It also shares memory between such filesystems and allows layers to be mounted in multiple places
For those familiar with how container images are built, this should make things a faster compared to the overlayfs techniques before. It also enables some kind of new hyper containerized software packages, but I'm not sure if that's a big deal. Something like how osx mounts a risk image for install or use