This DEV-only field was added in 836331ba5f69f2cc53b273ec073fae116db14302 by @sebmarkbage but it's not being used anymore to my knowledge.
readContext,
  prepareToReadContext,
  scheduleWorkOnParentPath,
} from './ReactFiberNewContext.new';
import {renderWithHooks, bailoutHooks} from './ReactFiberHooks.new';
import {stopProfilerTimerIfRunning} from './ReactProfilerTimer.new';
import {
  getMaskedContext,
  getUnmaskedContext,
  hasContextChanged as hasLegacyContextChanged,
  pushContextProvider as pushLegacyContextProvider,
  isContextProvider as isLegacyContextProvider,
  pushTopLevelContextObject,
  invalidateContextProvider,
} from './ReactFiberContext.new';
import {
  enterHydrationState,
  reenterHydrationStateFromDehydratedSuspenseInstance,
  resetHydrationState,
  tryToClaimNextHydratableInstance,
  warnIfHydrating,
} from './ReactFiberHydrationContext.new';
import {
  adoptClassInstance,
  constructClassInstance,
  mountClassInstance,
  resumeMountClassInstance,
  updateClassInstance,
} from './ReactFiberClassComponent.new';
import {resolveDefaultProps} from './ReactFiberLazyComponent.new';