War Era universe

The Book of the War described the state of reality during the War in Heaven as the "War Era universe", viewing it as distinct both from the pre-War version of reality, and what would follow it. However, it did not correspond to a single state of history, but to an entanglement of them: the timelines of all the planets in the Spiral Politic were constantly rewritten for as long as the War lasted. (PROSE: The Book of the War)

From the perspective of the post-War universe, by some accounts, this state of reality was an overwritten palimpsest. (PROSE: Father Time, The Gallifrey Chronicles)

The Last Great Time War, a time war whose exact relationship to the War in Heaven was a point of contention between many dissenting account, (PROSE: The Eyeless, The Paradox Moon, etc.) was also documented in some sources to have constituted a distinct "Time War timeline". (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe)

Timeline
The War in Heaven had, by most accounts, a complex constantly-rewritten timeline, (PROSE: The Book of the War, The Brakespeare Voyage, et al.) although one source indicated it was completely coterminous with the infected timeline. (PROSE: The Ancestor Cell)

By some accounts, this timeline was erased from existence, (PROSE: The Ancestor Cell, et al.) although others indicated a more complex situation. (PROSE: The Story So Far..., Weapons Grade Snake Oil)

Behind the scenes
In his piece "Future" for the charity anthology Perfect Timing 2, Lawrence Miles gives temporal mechanics applicable to the future timeline seen in his novel Alien Bodies. In a Time Lord textbook, the occasion of a Time Lord discovering their own future death is discussed as creating a paradox in the Observer Effect which would violently alter the nature of time. Much as The Book of the War describes the War's timeline as being more of a shape than a linear chronology, "Future" states that the change of events which would result from this occasion would affect the "very shape of the future".