Typical repository setup for SVN
the main line of development, the leading edge, where developers usually commit their regular changes.
a collection of snapshots of the trunk (or a branch) at a user-defined point in time, for instance release day.
active variations of the project compared to the trunk (or even another branch). This is useful when working out a (big) change that needs to be coordinated in a team or when using a single working-copy for the work with the changeproject is not feasible.