Thanks for the explanation.

But what I really want to know is: can I go from B departures to Z departures and back again with no security check and no passport check? A is Schengen, so I would expect there to be a check before entering.

Logically, movement from B departures to Z departures, and from Z departures to B departures, should need no passport or security check… After all, both are non-Schengen and clean, so why keep people in those areas separated? But in FRA you never know- not even people who work there understand it fully.

FRA is absurdly complex, which is why I’ll keep searching for connx thru MUC or ZRH. They really should consider knocking FRA down and starting again😂.