Brake fluid coming out of firewall

No lines are fine abs and and brake light came on and it was out of brake fluid so put some in and if you tap the brakes it leaks from a small pipe coming out of firewall any suggestions what would even be there we tried Google and diagrams and nothing comes up even a certified mechanic says nothing with brakes should be hooked into firewall thanks for the reply

I tried to post pic but don't know how it's my first time on here thanks

No sorry not familiar it's just the firewall with a small circle with liquid coming out when you push break pedal thanks