Take advantage of extension methods to add functionality to existing types without needing to modify or derive from those original types. In the C# programming language, extension methods enable you ...

File-based apps, extension members, nameof improvements, and user-defined compound assignment operators make life easier for C# programmers. You’ll need .NET 10.

This is a little more informative, but you still can't tell what's really going on, because it's magic. If you could peer inside the My.Forms feature, you might find Visual Basic adding parallel form ...