NSCompositingOperation examples anywhere?

Question

I'd like to explore some of the more obscure NSCompositingOperation options, like NSCompositingOperationColorDodge and NSCompositingOperationSoftLight and so forth, to find the right way to implement a particular effect I want in my app. All I can find about them is the AppKit doc, which has just a couple of words about each and seems to have no visual examples at all (as far as I have found, using Dash). Google provides essentially nothing about them. I did find a reference on one web page to an old Apple Developer example app called CompositeLab, but it doesn't seem to exist any more (indeed, Apple seems to have taken down all of their sample code and examples, or I haven't been able to figure out where they're hosted nowadays – what happened there??). Ideally, I'd love to have an app (like I guess CompositeLab was) where you could provide a "source" and "destination" image (or just a color value for them, optionally) and see the result from each compositing option. Does such a thing exist somewhere? How are people meant to discover the utility of these options? Or does nobody use them because nobody really knows what they do?