private static FileStatus[] getSequenceIdFiles(FileSystem walFS, Path regionDir)
    throws IOException {
    // TODO: Why are we using a method in here as part of our normal region open where
    // there is no splitting involved? Fix. St.Ack 01/20/2017.
    Path editsDir = getRegionDirRecoveredEditsDir(regionDir);
    try {
      FileStatus[] files = walFS.listStatus(editsDir, WALSplitUtil::isSequenceIdFile);
      return files != null ? files : new FileStatus[0];
    } catch (FileNotFoundException e) {
      return new FileStatus[0];
    }
  }
Is the given file a region open sequence id file.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALSplitUtil.java