This DEV-only field was added in 836331ba5f69f2cc53b273ec073fae116db14302 by @sebmarkbage but it's not being used anymore to my knowledge.
const nextProps = workInProgress.pendingProps;
  
  if (__DEV__) {
    if (shouldSuspend(workInProgress)) {
      workInProgress.flags |= DidCapture;
    }
  }
  let suspenseContext: SuspenseContext = suspenseStackCursor.current;
  let showFallback = false;
  const didSuspend = (workInProgress.flags & DidCapture) !== NoFlags;
  if (
    didSuspend ||
    shouldRemainOnFallback(
      suspenseContext,
      current,
      workInProgress,
      renderLanes,
    )
  ) {
    
    
    showFallback = true;
    workInProgress.flags &= ~DidCapture;
  } else {
    
    if (
      current === null ||