Typo at http://www.w3.org/TR/scxml/#Basic

   exmode  	false  	
	NMTOKEN 	"lax" 	"lax" or "strict" 	The execution mode of the
interpreter. This defines how the interpreter should behave if it
encounters an element or attribute that it does not understand. If
exmode is "lax", the interpreter will silently ignore element or
attribute. If exmode is "strict", the interpreter still not process the
element or attribute, but will also raise the error
error.unsupportedelement.


at http://www.w3.org/TR/scxml/#Basic should be


exmode 	false 	
	NMTOKEN 	"lax" 	"lax" or "strict" 	The execution mode of the
interpreter. This defines how the interpreter should behave if it
encounters an element or attribute that it does not understand. If
exmode is "lax", the interpreter will silently ignore element or
attribute. If exmode is "strict", the interpreter ***shall*** not
process the element or attribute, but will also raise the error
error.unsupportedelement.