CIA files are related to the CTR Importable Archive format used for 3DS games. An update like Update 12 for a CIA portable version would imply modifications to the game's data to work efficiently on a 3DS console, possibly including patches for homebrew or custom firmware users.
: The patch officially reinstated these four moves for use in Video Game Championships (VGC) and other online battle formats . pokemon ultra sun update 12 3ds world cia portable