paul,
That file contains numerous version of xml's used and adds a number as they are updated / changed.
The best thing to do is use a program like Acronis ( worth every penny and not that expensive ) and make an image file of your total hard drive. Acronis will reinstall the operating system, so if you have a crash or say get a virus, you can just reformat the drive and then put all back to the way it was in a fraction of the time ( it's quick ).
I would suggest saving all your xml's and additionaly other stuff like plug-ins, screens, etc which are not done with a fresh install of Mach to
a safe place. It's pain to have to look for say a wizard, or drilling routine ......
RICH