How to install and run RawTherapee 5.10* on macOS.
Once you’ve downloaded RawTherapee, open Downloads and double click on the new RawTherapee zip file.
Then double-click the RawTherapee dmg file inside the resulting folder.
When the fancy dmg pops up, drag the RawTherapee icon onto the Applications folder to install it.
To run RawTherapee, open Applications and double-click the RawTherapee icon.
*As of this writing, 5.10 has not been released, but dozens of you are currently testing it 