PhotoFlow (Alpha) is a fully non-destructive photo retouching program for Windows, Mac OS X, or Linux
https://github.com/aferrero2707/PhotoFlow/releases/latest Current status
PhotoFlow is in a early development stage (Alpha 0.3.0). The present version allows to open an image file and apply basic editing filters via non-destructive adjustment layers. The individual layers can be activated and de-activated using the radio buttons on the right of the image. Moreover, the layers structure can be saved to disk and re-opened again via the command line. Loading and processing of RAW images (demosaicing, white balance, exposure adjustment, etc.) is now available, at least at a basic level.
For Mac OS X you want the 0.3 PhotoFlow_git_stable_macos_20200828_1714_84720.dmg
https://github.com/aferrero2707/PhotoFlow/releases/latest