[xwiki-users] What does "author preserved" mean when importing and exporting?

Hi again, I am confused about http://platform.xwiki.org/xwiki/bin/view/AdminGuide/ImportExport#HExportingX... When exporting, there is the option "BACKUP PACKAGE (AUTHOR PRESERVED)", and when importing there is the option "Import as backup package". What does it mean that the author is preserved, since the contents of the author textbox are always saved in the package, and there is a separate checkbox to preserve the page authorship history? -Alex