What changed in an AccessibilityChange.
public enum AccessibilityChangeKind
Spec #33 viewer capability 8.
kind:method, kind:property, kind:ctor. Press Esc to clear.BoundsChangedThe viewport or layout changed, so every node's viewport bounds and offscreen state may have changed.ChildrenChangedThe children of Node (a page) were built or rebuilt.FocusChangedThe accessible focus moved to Node (null when it was cleared).