The option names all correspond to the names in Blender as well. Some options currently don’t have effect, aa samples, diffuse samples, glossy samples, simply because we don’t expose branched path tracing.
Cycles supports denoising yes, but we don’t have a good interface for that, nor would it work in our current viewport integration. Denoising is on the roadmap, not sure when it will happen.
all these options, wouldn’t it make sense that the presets from the dropdown in the rendering panel control some of these values?
I mean the quality dropdown (low, draft, good, final).
does it have any effect at all at the moment? has it influence on raytraced as well as CfR? wouldn’t it make sense, that raytraced should be faster so raytraced and CfR quality should have separate quality controls?
Long ago during the first stages of the integration development the quality drop down affected these settings, but that brought its own problems with it: the settings were found to be too arbitrary with too little room for user input.
I think that the drop down as such will see the end of its life in v7, probably to be replaced with presets that can be extended.