There is no official, standalone direct download link for just this specific .cab file on the Microsoft website . Instead, it is obtained through the following methods:
Windows 10 and 11 come pre-installed with newer versions of .NET, like version 4.8. However, they don't include the full binaries for version 3.5 by default to save disk space. The microsoft-windows-netfx3-ondemand-package.cab file contains the exact engine your computer needs to run apps built on .NET 2.0 through 3.5. Where to Safely Download It Microsoft-windows-netfx3-ondemand-package.cab Download