Seeking FSM for XML

Does anyone know of an (open source) Finite State Machine for XML, in any
format?

I made one years ago, but it is Bermuda Triangled now.

Please note, I don't want an XML format for FSMs. However, an FSM for XML
using an XML document type for FSMs would be great. I don't need a DTD for
the XML format for FSMs, but an FSM for XML which includes DTDs would be
great.

1.0 or 1.1

Cheers
Rick Jelliffe