Stores digital titles bought or installed on the system memory.

Play exclusive downloadable titles like Flipnote Studio , Shantae: Risky's Revenge , and Zenonia .

According to melonDS's official documentation, it is strongly recommended to dump the NAND from your own, legally owned DSi console. Methods for Obtaining NAND

This is the only fully legal and recommended method. It involves using a homebrew application on a compatible device (DS, DSi, or 3DS) to create a backup of its internal NAND.

Do it yourself. It is safer, legal, and guarantees compatibility.

A valid nand.bin file (typically 256 MB in size) contains:

Practical effects you’ll notice in melonDS