screenMasked

Whether a ScopeStack.maskScreen frame is what left screen null — i.e. the surface on display asserts it has no screen, rather than simply never having named one.

Both cases read as screen == null, and Autograph's own pipelines treat them the same way: they report no screen, and never substitute one from elsewhere. The distinction is published for a pipeline that holds a screen name from another source and has to decide whether the silence is an absence it may fill or an assertion it must respect — a mask is the latter, and filling it reinstates the screen the user just left (ScopeStack.maskScreen).

It is deliberately not a signal about history. autograph-compose's tap observer once fell back to ScreenHistory.lastScreen here and gated the fallback on this flag; the fallback is gone. History records what has been seen and outlives it by design, so it cannot answer what is on display, masked or not — every declaration in autograph-compose pushes a frame instead (TrackedScreen, a bare TrackScreenView, and NavController.TrackScreenViews all do).