Prerequisites
A: User must be logged in.

If the last release at particular Version tree is official, you should use this function to create a new editable working area or so called "New unofficial Release".

1. Select a Release by selecting
Project Name > Version Tree
See how

2. Select from drop-down menu (located on the top-right corner)
Release > New (unofficial)

New unofficial release will be created. Release contents will be cloned from the latest official release.

See also
Start Fixing Broken Packages, Make Release Official, View History of Releases