From the README on github:

momdec is a command-line tool for Mac OS X that takes a compiled Core Data model and decompiles it to produce an equivalent xcdatamodel or xcdatamodeld suitable for use in Xcode. The resulting model file can also be used with mogenerator to produce source code files for Core Data entities which have custom subclasses.

My latest open source project. A compiled managed object model contains enough information to reconstruct an equivalent editable model file. So, I thought, wouldn't it be interesting to actually do that?