Ah, sorry friend. It looks like xpps are generalized resource files (fittingly their magic is “KCAP”, PACK backwards), and they have a complex schema because they store basically general relational data it seems. Reversing would take quite a bit of work with the information currently available. If it’s any consolation, it seems like the merge may have been a bit of a monumental task to do correctly anyways given the enormous amount of metadata there is (just open up that file in a hex editor and see how small the text portion is, and how there appears to be multiple different metadata schema and sections). Sorry I couldn’t help, it’s a great idea.

I have some experience reversing binary formats. Depending on how complex it is (I unfortunately don’t have much free time to code) I may be able to write a utility or at least give you a guide to do it manually. Could you upload an example file and link it?