Disk Jockey v4 for macOS is out!
A better interface, a brand new Inspector for your files, support for more formats (NDIF, UCSD Pascal, Atari ST hard drives and more).
See your files' data as hex, preview their contents when possible (for example: read your AppleSoft Basic listings directly or check out Atari ST images in Degas format).
It still runs on Mac OS 10.13 and up (many bug fixes for the older versions) and it's still free.
Phew. I need a nap.