This ^
window._ppvPreviousPage
window._ppvInitialPercentViewed
window._ppvHighestPercentViewed
window._ppvFinalPercentViewed
window._ppvHighestPixelsSeen
window._ppvFoldsAvailable
window._ppvFoldsSeen
Are all the calls to return the cookies that are storing the values from the previous page, but you have to determine which dimensions should store the values.
From the documentation:
if(s.pageName) getPercentPageViewed();
if(_ppvPreviousPage)
{
s.prop1 = _ppvPreviousPage;
s.prop2 = "initialPercent=" + _ppvInitialPercentViewed + " | highestPercent=" + _ppvHighestPercentViewed + " | finalPercent=" + _ppvFinalPercentViewed + " | foldsAvailable=" + _ppvFoldsAvailable + " | foldsSeen=" + _ppvFoldsSeen;
}
Basically this is sending the "Previous Page Name" to prop1, and a concatenation of the various percentages into prop2.
Presumably, prop2 would then use Classification rules to process each individual value into its own classification.