C# Documentation vs Unity3D: Private vs Internal

I'm fairly inexperienced in C#, though Unity3D is sure a good excuse to read lots of C# documentation, and for that I'm grateful.

Question: Microsoft C# Documentation: Access Modifiers specifies that C#'s default access modifier is internal, not private. Yet my VS Code editor and a Unity question I saw here indicate the members are private by default. Why is Unity3D's version of C# different? I couldn't find a good post talking about this after a few google searches.