Ok now that I have answers on the "what", "when", "where" could somebody give me the "how" Berlin School relates to:
A new operating mode introduced in Page mode, Preview Perform is
very similar to EDIT mode but does not send MIDI notes like in
EDIT mode, allowing for “Berlin School” type performance.
From the default page mode, engage Preview Perform by pressing the
EDIT button twice (again, "twice", and not double-click!).
I fail to see the beauty of this mode…
I won’t ask for the "why".