File format
Identification/security bytes, checksums, name

0x0000
AA AC BD AF 90 88 9A 8D if inverted (xor with FF), the first eight bytes read "Ly755   ".
0x0008
D3 FF FE FF FE FF. These bytes are found in every Prizm add-in file
0x000E
The low byte of the inverse file size (at memory location 0x0013) minus 0x41. 
0x000F
This byte is always 0xFE. 
0x0010
Inverse filesize (four bytes). 
0x0014
The low byte of the inverse file size (at memory location 0x0013) minus 0xB8.
0x0016
FF FF
0x0020
A simple checksum (4 bytes long) is stored here. The checksum is calculated based on the entire file, except for this checksum and the copy of this checksum at the end of the file. 
0x0024
These two bytes are always 04 01.
0x0036
Size of executable code section (32-bit), minus the header size. This means that if this is equal to 0001445E, the copy of the 0x0020 checksum is at 0x0001545E. 
0x0040
Name of the Language. 
0x005C
Size of entire file (32-bit).[3][9] 
0x0060
Internal name. @ is always written before the name. 
0x0130
Version number string. Format: XX.XX.XXXX 
0x013C
Date/time created string. Format: YYYY.MMDD.HHMM 
File name, icons, executable code, checksum
________________________________________
0x0E9C
Language name (00 terminated). 
0x0EAC
Language salutation (00 terminated). 
0x0EBC
File name (including the .g3a extension). 
0x1000
Executable code section. This section will be mapped to virtual memory and executed when the user selects the language. 
Always begins with bytes 4C 59 37 35 35 00 00 00 02 (LY755    )
0x100A
Number of messages (possibly 0 base indexed) i.e  00 00 08 D2 = 2258 after the first message (#0) i.e. 2259 total
This value multiplied by 4 gives the offset of the first message vs the first
0x100A
00 00 00 00 - offset of the first message vs the first massage itself (i.e. zero ) 
0x1014, 0x1018...
offset of the subsequent messages vs the first one
0x????
Copy of the 0x0020 checksum. These are the last four bytes of the file. The location of these four bytes can be found by adding 0x1000 to the value at 0x0036.