Revisions allow you to track differences between multiple versions of your content, and revert back to older versions.
Don't know yet
You can view the list of demo files with this command:
Then this will show you where they are on your system
system.file("demo", "BivariateSaturated_PathCov.R", package="OpenMx")  "/Users/~/Library/R/2.9/library/OpenMx/demo/BivariateSaturated_PathCov.R"
(you need to add ".R" to the displayed name that demo() reveals)
Probably a good thing to add...