Quote:

---

     The name of the file is controlled via the sysctl(8) variable
     kern.corefile. The contents of this variable describes a filename to
     store the core image to. This filename can be absolute, or relative
     (which will resolve to the current working directory of the program gen-
     erating it). Any sequence of %N in this filename template will be
     replaced by the process name, %P by the processes PID, and %U by the UID.
     The name defaults to %N.core, yielding the traditional FreeBSD behaviour.

---