When should [assembly: InternalsVisibleTo()] be used?

Question

I understand that the InternalVisibleTo attribute is used to expose types and methods with the internal access modifier to a specified assembly. I have only ever us

Answer 1

Apart from testing, the only other scenario I've ever used the InternalsVisibleTo attribute, was when creating serialization assemblies.

Other than that, I've never used, nor needed it.