It doesn't currently, although some airlines looking at the A350-900ULR are considering adding some amenities in the cargo haul, which would be accessed via a s

It doesn't currently, although some airlines looking at the A350-900ULR are considering adding some amenities in the cargo haul, which would be accessed via a staircase similar to what some A340-600 operators did. The A350-900ULR is used by Singapore Airlines on the Singapore - New York flight that clocks 18 hours and a half. To be able to fly that far it needs to be light on payload: few passengers, no cargo. So there's some empty space in there...