Date and time the page was saved
Because every version of the page is saved, you can compare the current version of the page with older versions to see what changed. If you don't like what changed, you can restore an older version of the page. If you restore an older version and later decide you prefer the newer version, the new version still exists, so you can restore it.
You can't delete page versions. Because you can't delete page versions, it isn't possible for someone to edit the page without the page history tracking who changed the page and what they changed.
To view or restore previous versions of a page:
While viewing a page, click the View Document History (>) button at the upper-left of the page.
Select the version of the page you want to view.
To compare the currently viewed page version with the previous version, click Compare. New content is highlighted in blue, while removed content is highlighted in red with a strikethrough applied to the text.
To restore the currently viewed page version, click Restore and then click OK. The restored version becomes the active page version and is marked with the comment "Restored previous version date."