Some revisions have a special status. Those revisions have a specific revision icon and the status text is put in square brackets behind the revision number.
Revisions are part of the life cycle management concept that the ITP/MDK Repository provides for content. The life cycle of an object starts when you create a new object, which automatically gets the status [in development] when you close and save it. When you unlock this object it will get the status [current]. If a revision is tested and it has the right quality, it is promoted to the status [accepted]. To make an object available for the production run it has to be promoted to the status [published].