First, one must locate the marker by searching for 0x8b1202b96a612038727b930214d7a03213f5b9e6efae3318ee3b2dce24b36aae, then stepping back 8 bytes from the start of the market 
At this location, reading a long (little endian) will give one the absolute file offset to the single file bundle header. 
If the read value is 0, then it is not a single file bundle.
| offset | size | value | 
|---|---|---|
| 0x00 | 0x4 (D.W.) | major version | 
| 0x04 | 0x4 (D.W.) | minor version |