Aside from shock absorber fluid or gas, neither of which would leave a stain like that, I would say it is just normal dripping, moisture off the car. It may have been there longer than you think. Look at the salt staining around it. It used to be a bigger puddle then what you are looking at. My guess is that it was a chunk of ice frozen under the car that finally melted enough to fall out from somewhere. Even from the front.