Hi all. Recently I uploaded to Gerrit the Extension:TimeMachine. The idea for the extension came while developing for an old MediaWiki installation. Because the installation was so old, and I couldn't update, I was constantly checking mediawiki.org in search for old documentation, to see what worked and what not. Every time I had to go to the history tab of a page, go back to 2008 (when the version I was developing for was current), and look. So I thought: wouldn't it be great if I could just browse the wiki as it was in 2008? Then I thought this may be generally useful, so I created the extension to do so. I think that this functionality would be particularly useful in mediawiki.org, for users who need to browse old documentation. I suggest and propose that we improve the extension enough so that it can be deployed in mediawiki.org, and that we add a special page (or something similar) that allows users to select a MediaWiki version, and browse the wiki as it was when that version was current.
Topic on Project:Village Pump
If you want to get your extension deployed on MW.o, then it has to go through the process. See Writing an extension for deployment.
Thanks! I've started the design review process, I'll post a link to the design document soon.
Beware that there is significant effort in developing Extension:Memento: a very long review already happened on bugzilla.