Could not find a bug associated with this so opening one.
Would be nice to get some experimental version of it out, irrespective of whether it conforms completely to the microsoft counterpart.
Please also ensure that absolute-positioned children are supported inside of grid "cells".
I've noticed that IE 10 supports this in both "grid alignment" layouts as well as in "flexbox" layouts.
I bring this up because WebKit does not support absolute-positioned children inside of flexbox boxes as seen in WebKit bug 58453.
Here's the link to the official W3C draft:
It has graduated from the dev.w3.org server as "Grid Layout":
Marking this one as the duplicate, considering bug 60731 already has dependencies.
*** This bug has been marked as a duplicate of bug 60731 ***