http://msdn.microsoft.com/en-us/library/bb199633(v=xnagamestudio.40).aspx
Asset Name “AnimatedCube” – This is used to load the managed asset by using the ContentManager.Load method.

Content Importer “Autodesk FBX – XNA Framework” – The name of the importer for the related game asset. The list contains both custom importers referenced by the content project and standard importers provided by XNA Game Studio.

Content Processor “Animated Model Processor” – The name of the processor for the related game asset. The list contains both custom processors referenced by the content project and standard processors provided by XNA Game Studio.

XNA Standard Importers and Processors http://msdn.microsoft.com/en-us/library/bb447762.aspx

XNA Creating a Custom Importer and Processor http://msdn.microsoft.com/en-us/library/bb447754.aspx