Function normalizeIndexOutput

packages/next/src/utils.ts:3705–3713

(
  outputName: string,
  isServerMode: boolean
)

 * the server mode is enabled.
 */
export function normalizeIndexOutput(
  outputName: string,
  isServerMode: boolean
) {
  if (outputName !== 'index' && outputName !== '/index' && isServerMode) {
    return outputName.replace(/\/index$/, '');
  }
  return outputName;
}

/**
 * The path to next-server was changed in