Brake fluid leaked out of my rear wheel on my 96 Ford Bronco and made the brake light ome on what caused this?

Brake fluid leaked out of my rear wheel on my 96 Ford Bronco and made the brake light ome on what caused this?

You blew a brake line or w cyl then the light came on showing a brake failure, don't drive until fixed.

There's a switch in the brake lines that sensed a pressure imbalance when you got a leak. It shifted to the lower pressure side, closing the switch and lighting the light.
Repair the leak and bleed the system.
The light will go out when the pressure is balanced.