saxon:ptree serialization method
The serialization method
saxon:ptree causes the result tree to be output as
a PTree: see The PTree file format. This
is a binary XML format that occupies roughly the same amount of disk space as standard
lexical XML, but which saves time both on serializing and parsing, making it useful if the
data has to be sent to another machine for the next stage of processing.
With this method, all serialization properties other than