=item B<BookLearn> (default: false)
-Store learning information in the book (which must be writable). Currently
-no engine actually uses this information.
+This is a noop.
=item B<BookDepth> (default: 256)
This a bit vector in which each bit represents the processors that a
process is allowed to run on. This option works only on Windows.
+=item B<STFudge> (default: 20)
+
+PolyGlot will translate "st x" as "go movetime 1000*x-STFudge".
+The rationale is that in the UCI specification the argument of movetime
+is defined as the exact search time whereas the argument of the
+st command is only an upperbound.
+
=item B<OnlyWbOptions> (default: true)
If true then PolyGlot restricts the options it sends to those that