SD Filesystem
The 3DS uses an SD Card for general storage of additional game data and photos taken with the 3DS.
/DCIM - Photos /Nintendo 3DS - Game Data
Additional game data is stored here:
/Nintendo 3DS/<SomeID>/<SomeID>/extdata/00000000
0000033b - Ridge Racer EUR (Might be the same for all Regions) 0000022d - Face Raiders 00000227 - Mii Plaza