What does it even do ?
The view and render separates the amount of subdivision of viewport and actual render yes…so what does that leaves Quality to do ? This doesn’t exist in 2.79b…I don’t like change…I’m scared…
It has something to do with the switch to opensubdiv. I can’t remember what it does, but it is a setting that opensubdiv needed.
Check the release notes
Thank you for providing the link, after reading, it seems it is best to just let the default be and pretend things are as usual as though that setting never existed.