text: I spotted that too. I wonder if it should be trunk all the way from Crammond Brig to the junction with A902 – both of which are currently trunk.
  
  Otherwise the A902 & A199 from Leith to Portobello should be downgraded, which might actually make more sense. 
  
  The wiki suggests "Use highway=trunk for high performance roads that don't meet the requirement for motorway." which doesn't sound like a road through town bordered by houses!