CSS Grid Layout just shipped behind a flag (about:flags → “Enable Unprefixed CSS Grid Layout”) in Windows 10 Insider Preview build 16226.Robin Munn commented
The VMs available at https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/#downloads do not yet include Windows 10 Insider Preview build 16226: the latest VM available there is shown as "Microsoft Edge on Win10 (x64) Preview (16.16215)". Could you update those VMs to Preview build 16226? Many people don't want to run the Insider build on their HTML development machines (see https://wpdev.uservoice.com/forums/257854-microsoft-edge-developer/suggestions/13337121-release-alpha-beta-dev-builds-independent-of-windo for example), or may do Web development primarily on Linux because their Web server runs Linux. For both those user communities, an updated VM for testing Edge would be a great help.Robin Munn commented
The MS developer team has posted links to their status page for most of the other suggestions, but they seem to have missed this one. The status of the CSS grid update can be seen here: https://developer.microsoft.com/en-us/microsoft-edge/platform/status/gridupdate/
Its status is currently (as of March 7, 2017) listed as "Under Consideration", and no roadmap priority is currently visible.
This is something that we’d like to enable longer term. In the meantime, we have started to provide VMs for recent preview builds on dev.microsoftedge.com and are also working on a RemoteEdge solution to provide an app streaming solution based on Azure RemoteApp.
See http://blogs.windows.com/msedgedev/2015/07/14/bringing-componentization-to-the-web-an-overview-of-web-components/ (part 1) and https://blogs.windows.com/msedgedev/2015/07/15/microsoft-edge-and-web-components/ (part 2) for more information on our Web Components thoughts, plans, and roadmap.
The OGG container format is currently under consideration https://dev.modern.ie/platform/status/oggcontainer