This is a popular application for modded consoles that acts as a frontend menu for launching DS ROMs.
By modifying the DNS settings on your Nintendo DSi, 3DS, or a configured emulator (like MelonDS), you can bypass the dead Nintendo servers.
If you are looking to install this on a 3DS, I can guide you on how to use CFW to run it. Just Share public link
According to most intellectual property laws, you should own the original software or console to legally dump your own ROM file. Downloading ROMs of games you do not own is generally considered piracy.
For those interested in exploring Flipnote Studio, there are a few ways to get started:
If you're interested in creating flipnotes, you can explore official or unofficial alternatives that might be available for download or purchase.
You can copy the Flipnote Studio.nds file onto a MicroSD card, insert it into a DS flashcart (like an R4 card), and boot it on a DS or DS Lite.