Somebuildings that produce some goods, like shoes, have a yellow range around it, what is it?
I don’t know why that’s there during building placement either. It’s been asked before but haven’t seen a solid answer. Seems completely pointless.
It is somehow kind strange.
I can’t be certain but I think it shows you the range a fire could jump should it be allowed to spread to other buildings, though well placement also produces this and I don’t believe they can even burn.
Like this, when you place a wall?

From what I’ve been able to gather through observation, the yellow squares show you what spaces you will not be able to build because of other roads, walls and buildings. At first I thought maybe they had something to do with how far fire can jump, but wells are affected by this as well. Terrain features like lakes will also give you a yellow highlight showing you how close to the shore you can build. Unpathable terrain is another one, which may occur near very steep slopes. Slope too steep does not however give you a yellow square near your target build site. It just makes your target footprint turn red. You may also notice trees highlighting yellow, indicating you will need to wait for these items to be cut down. This can impact building and moving buildings equally, though sometimes I’ve had difficulty getting the trees to cut down for years on end until I just put my forestry camp area of effect over it and uncheck the fully grown only option.