What is Leith?

There's been a recent explosion of funny, rude, articulate graffitti on the grey hoardings opposite this long-persisting effort in chalk, but I was pleased to see that it had been retained(or possibly even reinstated!) since the refurbishment of the old tram depot building  - it's just to the left of the tree in Arclight's blip.

I think I feel another Fair Isle jumper coming on......