public static String getStage() {
    // strip out the "[stage] " wrapper
    return MDC.get(STAGE_KEY) instanceof String s ? s.substring(1, s.length() - 2) : null;
  }
Returns the current {@code [stage]} value prepended to log for this thread.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/LogUtil.java