What is this for?
When HBCb9 came out, they decided that they no longer need to support any invalid .elf files. If you have .elf files, you need to convert then to .dol with some little program that gets buried in some directory when/if you install devkitPro. This script will automate the task of converting all your stuff. It even comes with that little program so you don't need to install the entire devkitPro.