Paul Turner explained this really well at this year's Linux Plumbers Conference. The whole talk is fantastic, but the explanation of what pron is describing in

Paul Turner explained this really well at this year's Linux Plumbers Conference. The whole talk is fantastic, but the explanation of what pron is describing in particular (and how it could be improved) starts around 8:39: https://www.youtube.com/watch?v=KXuZi9aeGTw#t=519 https://www.youtube.com/watch?v=KXuZi9aeGTw#t=519