Yeah, cool stuff man.
I'm not sure yet what to think about the feature but there's now a cool zone-system-esque module called "Tone equalizer" which defines 8 zones to the picture and you can manipulate them by pointing to something in the picture and wheeling your mouse to push or pull that zone. Not exactly Silver Efex but cool nonetheless.
I don't think it works perfectly yet but I can't but wonder: is it allowed to have tools this easy?
What was introduced in 2.6, "filmic" to replace base curve when desired, is now obsolete and "Filmic RGB" is a rewrite of that feature. It works better, yes. I still base most of my work on the default base curve and tone curves.
Speaking of tone curves, the major reason to use tone curves for me are the film emulations
by Joao Pedro Almeida. When that is selected, I do local adjustments and sometimes go deeper into curves to achieve local contrast ("Clarity" in Adobeland) and other things.
Well now Darktable 3.0 has full support for LUT files, including these HaldCLUT png files. There's an absolute wealth of film emulations distributed as luts that I previously couldn't use via Darktable. I think some of the AGFA emulations you've already seen in some of my recent uploads... With LUTs there's the problem that now you need three files instead of two, to reproduce an image. The original raw file, the sidecar file and now thirdly, the LUT file. We'll see what happens.