ncmpcpp: playlist + library layout

I'm trying to replicate this ncmpcpp configuration

found on ArchLinux BBS.

It features a double-paned playlist window: on the left it shows a classic playlist, on the right there is a file browser (by default on window 3).

On the entire internet this is the first time I see such config, and I'm trying desperately to emulate it, without success. I've already tried tmux, but this seems far from a splitw -h, since the upper and lower parts of ncmpcpp are perfectly integrated with both panes.

Any hint?

It turns out that it is obtained by pressing CTRL + L, setting a splitting width and pressing the number of the screen to open (e.g. 5 for media library). As of 0.5.10 there is no way to set the split to persist a quit.