What would cause clucth fluid to leak out of front of tranny?

A hydraulic clutch is a sealed system with a small amount of fluid, and if it were to be leaking, almost immediately the clutch would be rendered inoperable.

The front end of a manual transmission, is called the bell housing, and typically the casing is all one piece, so the front section, or bellhousing, is what encases the actual clutch kit and should have no fluid in it at all, as typical automotive clutches are dry. Fluid leaking from the front of the transmission, where it is bolted to the motor, is likely motor oil from the rear main seal, which is where the transmission shaft enters the motor, within the center of the clutch. This is one of the few leaks that need to be addressed immediately, if the vehicle is still operable, it wont be for long. Once the clutch plates are saturated with the leaking motor oil, they are compromised, and the entire clutch kit will need to be replaced, in addition to the failed rear main seal. In both cases, the transmission needs to be removed so it is labor extensive, and not a job for a novice mechanic. Reinstalling the transmission is even more difficult than removing it. "It's just a minor leak" does not apply here.