The linked "article" is confusing, but the issue seem to be this: The C# language server for Visual Studio Code (the components which provide language-aware UI

The linked "article" is confusing, but the issue seem to be this: The C# language server for Visual Studio Code (the components which provide language-aware UI like tooltips, code completion, squiggles etc.) is currently fully open source, but MS is going to refactor it to incorporate some closed source components. It is not really clear to me why they are doing this and what they hope to achieve. Perhaps they want to create a for-pay "premium" version of the component? VS Code is probably cannibalizing Visual Studio sales. If enterprise customers move from Visual Studio to VS Code, MS will lose lots of money.