Expanding a stream in the Administration view or the Repository view tree shows the 'History' item. Select this to show the stream history in a window on the right.
The stream history shows every changeset that was submitted in this stream chronologically. So this is the complete timeline for the stream. The history also displays when child streams were created in blue. So you can see what changes were submitted before the stream was created. This could be useful for example to see whether a bug fix was included in a release.
Double-click on a changeset to open the Changeset Dialog to view which files were changed and to display the file differences. The Changeset Dialog is described in detail in the User Guide 'Submitting Changes' section.