There are a pair of related specs by Herbert Van de Sompel to allow "time travel" among versions on the web:
Briefly, RFC 7089 says that our HTTP server should accept the Accept-Datetime header as a request for an old version of a given article. We'd then look up the revision ID active at that datetime and return the appropriate version of the page, with a Memento-Datetime header in the response.
RFC 5829 says we ought to add <link rel="version-history"> <link rel="latest-version"> <link rel="predecessor-version"> etc tags to our <head>.
If we honor Accept-Datetime, third-party clients which annotate or refer to wikipedia resources can easily get to the proper version of the resource based on timestamp, without having to grok our bespoke revision ID scheme. This means the annotations can be guaranteed to apply correctly, even if the article has been changed since they were made.