xetex processes input in two stages. in the first stage xetex outputs an extended dvi (codice_2) file, which is then converted to pdf by a driver. in the default operating mode the codice_2 output is piped directly to the driver without producing any user-visible intermediate files. it is possible to run just the first stage of xetex and save the codice_2, although there are no viewers capable of displaying the intermediate format.