Explain what the two braided brake lines under where the driver's door is located purpose?

If they really are brake lines you answered your own question. They are brake lines. High-quality brake lines are braided. But if possible, a picture would really help, to make sure

You mean under the van, follow them. They are probably for the rear brakes Or could be gas-return lines to the tank

Oops, just now saw that they are leaking. So if it's brake fluid, there you are. Keep an eye on the fluid level in master cylinder