It probably seems fragmented because it's easy to get things confused, and Microsoft isn't making life easy during their journey in open sourcing the whole stac

It probably seems fragmented because it's easy to get things confused, and Microsoft isn't making life easy during their journey in open sourcing the whole stack (or at least significant portions of it). There's the languages (C#, F#), there's the runtime (CLR - Common Language Runtime), and then various frameworks (including the base framework, and the ASP.NET framework). Then there's the difference between the original variants of these and the new 'Core' variants. Plus there's various other related bits like the .NET Standard projects which are meant for library developers to target to make library cross-platform portability easier. As for difficulty getting intellisense working via emacs - that's certainly been something demoed, but it's not really a well tested use-case at this time. If you're coming at it from a non traditional (Windows) developer perspective - then you're looking at a massive ecosystem in flux and in migration from being a primarily single platform to multiplatform.