If I remember correctly, MSKey4in1 (or one of the other keygens with similar functionality) was released with source code, but in general, you said it yourself: after all, "cracking communities" are effectively people who don't need source code to understand or modify software.

The one person (Empress) that knows how to crack Denuvo refuses to share any details, and I think they recently had some kind of mental breakdown and will no longer be making any new game patches.