- DataUtil.cs: various data conversion classes
- JsonUtil.cs: converts to JSON format
- StcBinaryReader.cs: decrypts files
- Downloader.cs: downloads JP/EN/KR/CN files
- Program.cs: main program
The .format files in the STCFormat folder contain the names for each name-value pair in the JSON. These may need to be updated over time with client updates. girlsfrontline-deobfuscator may be a useful reference though it has not worked with recent client updates. Also see gfl-data-miner-python as they have a much better idea of what they're doing then I do.