NSP / Nintendo Submission Package (PFS0)

Main file games are distributed in. It contains multiple files inside (mainly nca).

Structure

Offset	Value	Type
0 to 3	Magic Number (PFS0)	UInt8
4	File Number	UInt32 LE
8	String Table Size	UInt32 LE
16 + (24 * File Number)	String Table Start	UInt8
String Table Start + Size	Data Offset	Nca

The String Table is a list of file names separated by NULL (U+0000).
The Data section has multiple Nca files, each file can be found at offset 16 + fileN * 24 where fileN is the number of the file (EX: 3) starting at 0.

NCA / Nintendo Content Archive

These files contain code, assets and other, the contents are encrypted mainly with AES-128-XTS (Variant of ECB) and AES-128-CTR.

Structure

Offset	Value	Type
16 + fileN * 24	Body offset	BigUInt64 LE
16 + fileN * 24 + 8	File size	BigUInt64 LE
16 + fileN * 24 + 16	File name offset	UInt32 LE

Note: The 16 in front is the Header offset which always is 16 but is kept separate incase of future modification.

The File Name Offset is the offset for the string table.
The file contents are found at offset Body offset + Data Offset.