-function object. This is explicitly allowed by the ANSI standard, but
-leads to some oddities, e.g. collapsing @code{functionp} and
-@code{compiled-function-p} into the same predicate.
+function object. A more traditional interpreter is also available on
+default builds; it is usually only called internally. This is
+explicitly allowed by the ANSI standard, but leads to some oddities;
+e.g. at default settings, @code{functionp} and
+@code{compiled-function-p} are equivalent, and they collapse into the
+same function when SBCL is built without the interpreter.