Q: Why is this necessary?
A: If you want to hack on the Minecraft Wii U Edition, then you need this.

Q: How do I put this on my SD Card?
A: Open Up The Zip file and put the tcpgecko folder into your SD Card. Once it's in your SD Card, put it in the wiiu file if you have homebrew. Then put it into the apps folder, and your done!