A WOZ file accurately stores Apple II disk data. The WOZ format represents disks including ones with copy protection. WOZ files contain metadata like disk name and publisher. The WOZ format is easy to implement in emulators. Emulators can display disk metadata.
The WOZ format was released in 2018. It comes from the Applesauce project by John K. Morris. The goal is to simply store Apple II disk data. WOZ files start with a 12-byte header. The header identifies the file type. It also detects corruption. The first 8 bytes hold the WOZ signature. The last 4 bytes CRC the remaining data.
Macintosh Repository has served over 5 million old Mac files. Recent downloads total over 1.3TB. The WOZ format recreates protected Apple II disks. This allows original software use in emulators. MicroM8 emulator supports WOZ reading and writing now. Its library has 1300 WOZ images.
New WOZ exporting code will enable more WOZ file creation. Some emulators like MAME and MESS support WOZ already. More emulators likely will over time. WOZ files accurately replicate Apple II disks for preservation. The format is easy to implement in modern software.