Backlog, Release, Freeze and Done
Four of the Software elements are not where work is done, but where it waits, ships or finishes. They carry little or no Effort; their job is timing.

Backlog
Section titled “Backlog”The Backlog is where a work item waits to start. An item waits there until two things are true: every row it Depends on is Done, and a person has room. It has no effort. On a small plan the dependencies, not the people, usually set the finish, so the Backlog is where you look first when a date slips. See The Work Table.
Release
Section titled “Release”A Release step ships a release. An item reaches it when its work is done, and the release waits there until every item in it is done. It has no effort. Give its People box plenty of room, so an early release is never stuck behind a later one. The product will say so before the run if the box is too small.
Freeze
Section titled “Freeze”A Freeze shuts the Release step for a window, so nothing ships in that time. It is the code freeze before a launch: the team keeps working, but releases hold until the freeze lifts.
The Done stop is where a work item finishes and is counted. Its Kind of step is Other: it does no work and takes no effort, it simply marks the end. Everything that reaches Done is what the Forecast counts as delivered.

