Microsoft details how .Net split to .Net Core and .Net Framework

I will be back writes: Immo Landwerth added few more detail on the Open Source .Net Core. Using recipes from mono cookbook .Net Core was built modular as unified Base Class Library (BCL), so you can install only necessary packages of Core and ship it with application using NuGet. So NuGet becomes the first class citizen and the default tool to deliver .Net Core packages.
As smaller and cross-platform subset of .Net Framework it will have it's own updated schedule and will be updated few times a year, where .Net will be updated once a year. At a time of release of .Net 4.6, Core will be a clear subset of .Net Framework. With future iterations it will be ahead of .Net Framework and some features of new versions on .Net Core will not be available in current .Net Framework but will be synchronized on a next release.

The .NET Core platform is a new .NET stack that is optimized for open source development and agile delivery on NuGet. We’re working with the Mono community to make it great on Windows, Linux and Mac, and Microsoft will support it on all three platforms.