XCF
From Just Solve the File Format Problem
Revision as of 00:43, 20 February 2013 by Dan Tobias (Talk | contribs)
XCF is the native file format for GIMP (GNU Image Manipulation Program). It supports all the possible information about an image, including layers and transparency, except for undo information[1].
The Wikipedia article says that the reference documentation is the source code for GIMP itself.