Looks like Tar Spot.

https://www.mortonarb.org/trees-plants/tree-and-plant-advice/help-diseases/tar-spot-maple-rhytisma-spp

https://hortnews.extension.iastate.edu/maple-tar-spot

the link above says it better than i could: causes a great deal of concern for home gardeners due to its appearance. Luckily, this disease is generally a cosmetic problem, rather than a real health issue for trees.

if also says in summation: Fungicides are available to treat tar spot proactively in spring, but are seldom recommended since tar spot does very little damage to the tree. The cost of treatment may outweigh the benefits.

==no your tree is not sick ...

its got ugly leaves ... so what ..

99.9% of each food making machine is unaffected.. ergo.. doing its job ...

ken

It's probably Phyllosticta leaf spot rather than Tar Spot, still not a serious issue. Here's a fact sheet that has a brief description of both.

If this is a fungus on the leaves, then is it OK to use these leaves as mulch in the garden? or in the compost? Good to hear it is not a serious issue (especially to the tree).