Lambs quarter?

Yes. One of the Chenopodiums.

Thanks!

Wow, Chenopodium looks like a superfood weed!

"Lamb’s quarters - also called wild spinach - is one of the most nutritious greens ever analyzed, outcompeting many common vegetables (including domestic spinach) in vitamin and mineral content. However, it is also high in oxalates, for which there are some precautions - these are outlined in detail at the end of this article."

I’d be wary of eating a plant growing in a sidewalk. I’d rather find a less polluted source.