What is "NotConvertedAttribute"?

Hi, could someone maybe explain what NotConvertedAttribute is supposed to do? The unity document on this: http://docs.unity3d.com/412/Documentation/ScriptReference/NotConvertedAttribute.html is kind of vague and I didn’t get back any good result from Google :frowning:
Much appreciated!!

The documentation is sparse, but it has to do with type conversion during building.

http://docs.unity3d.com/412/Documentation/ScriptReference/NotConvertedAttribute.html