This DEV-only field was added in 836331ba5f69f2cc53b273ec073fae116db14302 by @sebmarkbage but it's not being used anymore to my knowledge.
const ref = workInProgress.ref;
  if (
    (current === null && ref !== null) ||
    (current !== null && current.ref !== ref)
  ) {
    
    workInProgress.flags |= Ref;
    if (enableSuspenseLayoutEffectSemantics) {
      workInProgress.flags |= RefStatic;
    }
  }
}
function updateFunctionComponent(