These downloads are for application development of Managed C# Managed Code applications with a Windows Embedded Compact 2013 OS SDK. These use the Compact Framework 3.9 and are developed in Visual Studio 2012 with an installed SDK built from a Compact 2013 OS project.
Note that there is no generic SDK for Compact 2013. It has to be built for and from an actual Compact 2013 project.
The AboutBox (CF3.9AboutBox.zip)
When installed it adds an Item Template to Visual Studio 2012 for
a Windows Form that implements a typical AboutBox.
The code is ported from the desktop version.
See Documentation for details