ROM Hack .chres files and how to open/view them?

[luckyk]

Hi, everyone. I'm kind of a 3DS rom hacking novice, only having worked on a few Animal Crossing retextures before this. I was looking at Cooking Mama 5 and noticed that nearly all the major files for the game were in a format called .chres. Spica and the Kuriimu suite don't seem to support them at all, and I have no idea how you would go about modifying these files. Do any other games use them? Are there any known ways to view or open them?

Edit: Zero results on 3Dbrew either. In fact, nothing 3DS-related even appears on Google when searching for "chres file."