Saxon extensions to the W3C XSLT/XQuery specifications
A new attribute saxon:explain
is available on any instruction in the stylesheet. The permitted
values are "yes" and "no". If the value is yes, then at compile-time, Saxon outputs an analysis of all
XPath expressions appearing in attributes of that instruction. The analysis includes the static type
of the expression, and a representation of the optimized expression tree. For some examples, see
Saxon Extensions.