I think the title really undersells it, the video is worth a watch. It's really an impressive effort just to get .NET 3.5 code running on Windows 95, seemingly just to be able to say he could.

HN is usually good for this kind of thing: it looks like NDP is an internal name for dotnet, does anyone here who remembers what it stood for?

There is also a video on his yt channel going through the process (and pain) of creating the backport. https://www.youtube.com/watch?v=CTUMNtKQLl8