On line 51, .FB should be \fB:
.TP
.FB-exn-history \fI{\fBtrue\fI|\fBfalse\fI}\fR
Enable \fBExn.history\fP. This has a performance impact, both in memory usage
of exceptions and in runtime, because of additional work that must be performed
at each exception construction, raise, and handle. By default, it is disabled.