Looks like Tar Spot. Quite common on maples during cool wet springs.

I wouldn't worry about it unless it worsens and your tree defoliates early this fall. At that point you have to be diligent in cleaning up the leaves and may want to consider treatment the following year.

thanks. it was thinking Anthracnose or tar spot. tar spot pics i googled seemed raised up, these spots aren't raised. but treatment seems the same.

Tar spot. Usually doesn't harm the tree unless severe.