CTR Executable Image (CXI)
A file that typically contains a game's code and assets. Regions:
NCCH header
Extended Header
Logo region (optional)
Plain region (optional)
ExeFS (optional)
RomFS (optional)
CTR File Archive (CFA)
A file that typically contains a game's manual, Download Play child CIA, gamecard system update files, or DLC contents. Regions:
NCCH header
ExeFS (optional, no ARM11 code)
RomFS (optional)
CTR Cart Image (CCI)
Used on game cards. Usually ends in three extensions:
.3ds for gamecard dumps
.cci for development images
.csu for updating titles on developer units.
CTR System Utility/Update (CSU)
Used for updating developer units. Same format as CCI.
CTR Importable Archive (CIA)
Can be installed on a developer unit or retail console with signature patches (e.g. via Custom/Modified Firmware). Regions:
Certificate chain
Ticket
Title metadata
Contents
Meta region (optional)
ROM Spec File (RSF)
Used when [re]building CCI, CIA & NCCH containers.
NCCH regions
NCCH Header
Contains information such as title ID, product code, encryption method, etc.
Extended Header (ExHeader, ExtHeader)
Contains information about accessible services, system modules, etc.
Logo Region
Contains the "Nintendo 3DS" logo animation when launching an application. On titles for versions below 5.0.0-11, this is inside the ExeFS.
Plain Region
Contains information about the SDK version and other tools used.
Executable Filesystem (ExeFS)
Contains the code, banner, and icon. On titles for versions below 5.0.0-11, the Logo is also included.