private static boolean usingTemplate(byte flag) {
    return (flag & 0x01) == 1;
  }
Including schema and pre-delete flag of a measurement, could be expanded further.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/schemafile/RecordUtils.java