It is used to compress and decompress CGSS LZ4 archives.

The header format of LZ4 archives used in CGSS is different from standard LZ4 archives.

LZ4.exe <file>

• File: The file to compress or decompress. If the name of the file ends in ".lz4", the utility decompress it; otherwise the utility compresses it.

LZ4.exe jacket_1001.unity3d
LZ4.exe jacket_1001.unity3d.lz4