At least I think it is a junction box. There are various sizes of these boxes around town and they all used to be painted green often with graffiti on them. I am not sure if these new ones are for Fibre or Power ( it was about the time Fibre was installed here that the boxes started to be painted).
This is my favourite and one I see on leaving Max' Rest Home as it is straight across the road.
We have finally had some showers today. Wonderful. Hopefully, we will have more over the next few days.