This DEV-only field was added in 836331ba5f69f2cc53b273ec073fae116db14302 by @sebmarkbage but it's not being used anymore to my knowledge.
import {disableLogs, reenableLogs} from 'shared/ConsolePatchingDev';
const ReactCurrentOwner = ReactSharedInternals.ReactCurrentOwner;
let didReceiveUpdate: boolean = false;
let didWarnAboutBadClass;
let didWarnAboutModulePatternComponent;
let didWarnAboutContextTypeOnFunctionComponent;
let didWarnAboutGetDerivedStateOnFunctionComponent;
let didWarnAboutFunctionRefs;
export let didWarnAboutReassigningProps;
let didWarnAboutRevealOrder;
let didWarnAboutTailOptions;
let didWarnAboutDefaultPropsOnFunctionComponent;
if (__DEV__) {
  didWarnAboutBadClass = {};
  didWarnAboutModulePatternComponent = {};
  didWarnAboutContextTypeOnFunctionComponent = {};
  didWarnAboutGetDerivedStateOnFunctionComponent = {};
  didWarnAboutFunctionRefs = {};
  didWarnAboutReassigningProps = false;
  didWarnAboutRevealOrder = {};
  didWarnAboutTailOptions = {};
  didWarnAboutDefaultPropsOnFunctionComponent = {};
}
export function reconcileChildren(
  current: Fiber | null,
  workInProgress: Fiber,
  nextChildren: any,
  renderLanes: Lanes,
) {
  if (current === null) {