why does the engine want the bishop on f8 instead of e7. I see the bishop f1 or f8 manoeuvers appear very frequently in grandmaster games and it seems to be a common strategic concept. why place the bishop here in the middlegame?
The bishop stands better at f8: protects g7 and does not stand in the way of Re8. For example ...Bf8 Ne5 bxc5 Nxc6 Bxc6 Nf3 Nd7 dxc5 e5 where ...e5 would be impossible with the bishop on e7.