How to get all of the supported file formats from Graphics unit?

When any TGraphic descendant registering its own graphic file format with a class procedure TPicture.RegisterFileFormat(), they're all stored in Graphics.FileFormats global variable.

Too bad that FileFormats variable is not in the "interface" section of "Graphics.pas", so I can't access it. I need to read this variable to implement a special filter for my file-list control.

Can I get that list without manual fixing the Graphics.pas's source code?