The crazy high numbers are due to a fairly Microsoft-specific definition of "API" in this context. What they count here is class members; so they ported a class with 15 methods and 3 properties, they'd count this as "18 APIs" (or perhaps 19 - not sure if the class itself counts as an "API" as well).
That being said, I'm sure there was indeed an impressive amount of code that had to be ported.
I think the point was that often "an API" means a larger collection of functions, classes, properties, etc. Like the COM API, the DirectX API, the MFC API and so on.
Yes, that's what I meant. The use of the term "API" for a single public code element is something I have not come across in any other language community, hence the clarification for those who are not familiar.
It refers to the API surface area (classes, methods, namespaces available in the standard library) from .NET Framework, the Windows-only runtime that has been developed for the last 15 years.
.NET Core is the new cross-platform runtime and now supports more than half of all the API surface available from the older framework. The number itself isn't anything special but just denotes how big the standard library is.
It's massive and includes all kind of things from localization, networking, file system, threading, compiler, graphics, cryptography, web, text processing, XAML, OS etc APIs.
I don't know .NET at all and the numbers there seem mind boggling. Can someone put this into some kind of context?