+\fBnotRequested\fR, \fBdiagnostic\fR or \fBsubtree\fR.
+If \fIdata-type\fR is \fBnumeric\fR or \fBstring\fR then \fIdata\fR is
+encoded as a single Tcl token. The \fIdata-type\fR \fBbool\fR is encoded
+as 0 or 1 for false and true respectively. If the \fIdata-type\fR is
+\fBsubtree\fR the \fIdata\fR is a sub-list. In all other cases, the
+\fIdata\fR is the empty string.
+.TP
+.BI "" zs " getExplain " position " [" pattern " " pattern " " ... "]"
+The Explain record on the specified position is returned. See the
+manual for a detailed explanation.