I have published an app and editing it. One new "Rev" tab is created and it is giving me a dropdown as shown  here![enter image description here][1]. Why it is being created here? It is not created in any other StackExchange websites when we edit question. Is it related to

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as explained here: http://stackapps.com/q/7?


  [1]: https://i.sstatic.net/iSQtj.png