async function getSchedulerVersion(reactVersion) {
  const url = `https://registry.npmjs.org/react-dom/${reactVersion}`
  const response = await fetch(url, {
    headers: {
      Accept: 'application/json',
    },
  })
  if (!response.ok) {
    throw new Error(
      `${url}: ${response.status} ${response.statusText}\n${await response.text()}`
    )
  }

  const manifest = await response.json()

  return manifest.dependencies['scheduler']
}
Set to `null` to automatically sync the React version of Pages Router with App Router React version.
Set to a specific version to override the Pages Router React version e.g. `^19.0.0`.

"Active" just refers to our current development practice. While we do support
React 18 in pages router, we don't focus our development process on it considering
it does not receive new features.
@type {string | null}