This is a custom bundle for RavenDB. The current release requires RavenDB version 2.5.2700 or higher.
It allows you to make changes to a document that are effective at a particular point in time. Often, this will be "now", but it can easily be a past or future date. All version history is maintained.
The difference between this and Raven's official "Versioning Bundle" is that past changes are not hidden from you. You can load, store, delete, or query at any date - past, present or future.