The tree is totally normal, but there was a large branch cut off a long time ago because it was blocking the sidewalk. A small branch is growing out of that cut stump and all those leaves have the left half lobed and the right half toothed. No idea if its a graft, or just natural.
Is this a mulberry? It looks to me like a plant sport which is a variation arising from a single plant that differs genetically from the parent plant, it is essentially a mutation that manifests as a noticeable change in a plant's characteristics, it can sometimes happen when the cellular structure has been messed with (say cutting off a limb) and the dormant buds grow and divide in differing ways giving the variation in the leaf characteristics. It's just a guess though.
I agree, looks like a mulberry. Leaves on small trees and new branches are particularly likely to be lobed in mulberry, while older branches tend to produce leaves without lobes.
This is for strictly mildly interesting material. If it's too interesting, it doesn't belong. If it's not interesting, it doesn't belong.
This is obviously an objective criteria, so the mods are always right. Or maybe mildly right? Ahh.. what do we know?
Just post some stuff and don't spam.