The Outliner lists the scenes of a book in reading order, each reduced to its synopsis and its tagged story beats. It reads the same document tree as the Binder and the Corkboard rather than maintaining a separate outline document, which is what prevents an outline from describing a draft that has since changed.
Story beats
A beat records what occurs in a scene: a turn, a reveal, a decision. Beats are tagged against the scene and summarized in the outline, so a missing turn or a run of scenes with no beat is identifiable without reading the prose. Beats may be added before the scene is drafted or after it.
Synopses
A synopsis is one or two lines describing the scene. It is written once and then used throughout: it labels the card on the Corkboard, it appears in the Outliner, and it is what makes a scene identifiable in the Binder without opening it.
Reordering
Reordering in the Outliner reorders the manuscript, by the same mechanism as the Corkboard and for the same reason: all three surfaces address one structure. There is no step in which an outline is brought back into agreement with the draft, because there is no second copy to bring into agreement.