Microsoft today launched the UWP Toolkit, "a new project that enables the developer community to collaborate and contribute new capabilities on top of the [Windows 10] SDK."
The Toolkit is designed to simplify UWP app development. One example that Microsoft used was that it can make it easier to share content from your app to social media services, taking care of the OAuth steps "behind-the-scenes".
The package should be compatible with any UWP app written in C# or VB.Net, although it will need to be developed with the Windows SDK for build 10586 or above. This also includes Win32 apps that were converted to UWP using the Project Centennial bridge.
Microsoft also noted that it can be used to create apps for all Windows 10 devices, including PCs, tablets, phones, IoT, HoloLens, and Xbox. The company will be offering a sample app, which should provide examples of the capabilities of the Toolkit.
The UWP Toolkit is entirely open-source, and you can find the code on GitHub. You'll also be able to find the source code of the sample app that's available from the link above.
If you'd like to get started with the UWP Toolkit, you'll need Visual Studio 2015 Update 3, and in a UWP project, you'll have to add the NuGet package. You can find it by searching for "Microsoft.Toolkit.UWP".
Source: Windows Blog