What is leaking from my car?

Are you sure it's from your vehicle and not the one that was parked there earlier?

Hold moderate steady pressure on the brake pedal. If it slowly sinks to the floor, suspect the rubber flex hose is starting to leak next to that wheel. Brake fluid level will naturally go down as the front disc brake pads wear but that takes many miles to occur. All mechanics know to never add brake fluid to top off the reservoir during other routine service such as oil changes because that level will come back up when new brake pads are installed. If someone added previously, that fluid will spill over and make a mess when the new brake pads are installed. Brake fluid eats paint too. A leaking hose will get worse real quickly so don't ignore it.

There isn't much in the brake hydraulic system that can leak and be hard to locate. Engine oil is a different issue. You have to look for the highest point on the engine you see it. Valve covers and oil pans are two common leak sources. The rear main seal is in the same area but less common. That will leak oil onto the ground closer to the center of the car, but it's always possible for it to leak onto a cross member and run along it, then drip on the ground somewhere else. Dye can be added to engine oil to locate the source of a leak that's hard to find.