(Although it *does* mean that ImageMagick had better not be using any GIMP code to help out it's decode/display of XCF's or it'll be in breach of GPL)
No GIMP code - at least not verbatim.
We don't use glib and we have our own imaging engines, so all that stuff got rewritten but I did keep the general structure of loading pretty much the same so that it would be easy to make changes in the future.
If anyone from the Gimp team wants to review it for potential "too much copying and GPL infractions", please feel free and I will make any changes!
Leonard