My 99 ford taurus is leaking water from a small hold behind the alternator on the block what would that be?

My 99 ford taurus is leaking water from a small hold behind the alternator on the block what would that be?

Probably a coreplug that's rusted.

They are typically just press-fit or domed discs that expand when tapped in to place.
You pull the old one out, clean the hole and fit a new one.

More info:
https://en.wikipedia.org/.../Core_plug

Small hole? Is it where the head meets the block? Could be a bad head gasket. Or is there a freeze plug there?