In which folder exactly is the 3DS game data stored?

I bought a new Nintendo a long time ago and now after a long time I've found my old nintendo. I would like to transfer the memory data of the old SDHC card of my old Nintendos to the micro sd of the new one and my real question would be in which folder all the game data are stored so that I can copy the memory data of the old Nintendos into it.

Game data are usually stored on the cartridges themselves.

If you mean downloaded games that are not easily accessible, at least with all the games I had.