enabled rules in the startup theory
ACL2 concludes its initialization (boot-strapping) procedure
by defining the theory ground-zero; see theories. In fact, this
theory is just the theory defined by (current-theory :here) at the
conclusion of initialization; see current-theory.
Note that by evaluating the event
(in-theory (current-theory 'ground-zero))
you can restore the current theory to its value at the time you started up