I have just started to experiment with XProc. Prior to using XProc, I have been transforming XML with XSLT and the transformation scenario lets me select among a number of transformation engines such as various flavors of Saxon. When I run the transformation under XProc as a p:xslt step, I am getting some errors that didn't appear with Saxon. These are easily solved, but I wonder: (1) What XSLT engine is being used with XProc? Does Calabash provide its own engine? (2) Can I control which engine is being used within XProc? With thanks, David