public Set<TableName> getTablesIncludedInBackups() throws IOException {
    Set<TableName> names = new HashSet<>();
    List<BackupInfo> infos = getBackupHistory(true);
    for (BackupInfo info : infos) {
      // Incremental backups have the same tables as the preceding full backups
      if (info.getType() == BackupType.FULL) {
        names.addAll(info.getTableNames());
      }
    }
    return names;
  }
Retrieve all table names that are part of any known backup
hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupSystemTable.java