The Windows SDK (Windows Software Development Kit) for Windows 11 provides the latest headers, libraries, metadata, and tools for building Windows applications. Use this SDK to build Universal Windows Platform (UWP) and Win32 applications for Windows 11, version 22H2 and previous Windows releases.
They are software development kits (SDKs) from Microsoft that contain documentation, header files, libraries, samples and tools required to develop applications for Microsoft Windows and .NET Framework.
Version 10.0.22621.2428 for Win11 is a freeware program which does not have restrictions and it's free so it doesn't cost anything.
Virus and Malware Tests:
For security reasons, you should also check out the Microsoft Windows SDK download at LO4D.com which includes virus and malware tests. Additional screenshots of this application download may be available, too.