| Offset | Name | Length | Expected Value | Notes |
|---|---|---|---|---|
| x00 | Magic | 8 Bytes | x50 x00 x11 x00 x36 x50 x4b x30 | The last four bytes always contain 6PK0 |
| x08 | Width | 2 Bytes | Variable | Most likely width based upon similarly named sprite sizes |
| x0A | Height | 2 Bytes | Variable | Most likely height based upon similarly named sprite sizes |
| x0c | Unknown | 1 Byte | If the preceding entries are width and height, this may refer to 'Z' as a dimension, such as with 3d textures | |
| x0E | Total Files | 1 Byte | Variable | The number of file entries, starting from 0x50 |
| x50 | Decompressed File Checksums | 8 Bytes * x0E | Variable | Each int contains the decompressed file size |
| (x50 + (8 bytes * x0E)) | Compressed File Checksums | 8 Bytes * x0E * 2 | Variable | After reading each int, the next int is a control value of unknown purpose, which is commonly equal to 6 |
| Follows Compressed File Checksums | ZSTD Stream Start | 4 Bytes | x28 xb5 x2f xfd | ZSTD magic header. The number of ZSTD headers found in the file should be equal to the value of x0E |
Notes
- The format appears to be a forked version of the 6pack format, except using ZSTD to compress entries instead of fastlz
- Files are Little-Endian (LE) UTF8.
- 0x54 appears to indicate that the largest block size is 65536
- Block sizes were observed to run from the largest possible, decreasing by half until the end of the file
- Decompressed data resembles the ASTC image format, but attempts to take the decoded data and create ASTC files have not been successful