Let me introduce myself...

Welcome. I think you'll find lots of "non-bird" photography here. I'm also a user of only free photo-editing software. While I have tried ART and have used Rawtherapee, my software of choice is darktable (darktable). I have used GIMP as well, but not for most typical editing. Darktable is very powerful, which also means there are many options and many ways of using it. I have figured out the few modules that I need to use, so ignore most of it!

I can easily find the Raw Therapee download page that includes MAC operating systems. "ART" is based on Raw Therapee, is a "Fork" of it. both are similar, I just find ART easier to navigate. Both use the standard ".dcp" digital camera profile files, that are common with other processing packages including Lightroom. I tend to explore the installations of software and try things out. I copied the ".DCP" files that came with my LR6 on my Laptop to my tower computer running ART and Raw Therapee. It works on both "ART" and "RT". I also sent the ".DCP" file to another forum member here to use for his Leica, made a big difference in the colors being rendered. Darktable does not use ".dcp" files.

I documented some of the "tricks" on rangefinderforum. The same basic directory structure is used for ART and RT. I copied the .dcp files to the same place for both.