Any time you see the word "core" in an "open source" announcement such as
this, it's a huge red flag. Generally it means that only one specific
component is being "opened," and the majority of the framework (the actual
important bits that an application requires to run) is being kept "closed."
The word "core" might sound significant but we actually require the full
framework to get anything done.
In this case, the blog post explains that ".NET Core" is one specific part of
the .NET framework as a whole, and while they've already "opened" certain
other bits of .NET, they "do not have plans on open sourcing and enabling you
to build the full .NET Framework that ships in operating system."
https://github.com/dotnet/corefx/issues/82#issuecomment-63158393
