That's a bit misleading. It's a rebranded Xamarin Studio, which was based on MonoDevelop. But the a lot of the underlying engine and code renderers are based on Visual Studio now (as of 2019). The longer it is since it was called "MonoDevelop" the less "MonoDevelop" code is left. If 2022 has removed the GTK+ UI wrapper, I guess it is very distantly based on MonoDevelop now.