@Override
  public DeleteResult isDeleted(ExtendedCell cell) {
    long timestamp = cell.getTimestamp();
    try {
      if (hasFamilyStamp) {
        if (visibilityTagsDeleteFamily != null) {
          if (!visibilityTagsDeleteFamily.isEmpty()) {
            for (int i = 0; i < visibilityTagsDeleteFamily.size(); i++) {
              // visibilityTagsDeleteFamily is ArrayList
              Triple<List<Tag>, Byte, Long> triple = visibilityTagsDeleteFamily.get(i);
              if (timestamp <= triple.getThird()) {
                List<Tag> putVisTags = new ArrayList<>();
                Byte putCellVisTagsFormat = VisibilityUtils.extractVisibilityTags(cell, putVisTags);
                boolean matchFound = VisibilityLabelServiceManager.getInstance()
                  .getVisibilityLabelService().matchVisibility(putVisTags, putCellVisTagsFormat,
                    triple.getFirst(), triple.getSecond());
                if (matchFound) {
                  // A return type of FAMILY_DELETED will cause skip for all remaining cells from
                  // this
                  // family. We would like to match visibility expression on every put cells after
                  // this and only remove those matching with the family delete visibility. So we
                  // are
                  // returning FAMILY_VERSION_DELETED from here.
                  return DeleteResult.FAMILY_VERSION_DELETED;
                }
              }
            }
          } else {
            if (!VisibilityUtils.isVisibilityTagsPresent(cell) && timestamp <= familyStamp) {
              // No tags
              return DeleteResult.FAMILY_VERSION_DELETED;
            }
          }
        } else {
          if (!VisibilityUtils.isVisibilityTagsPresent(cell) && timestamp <= familyStamp) {
            // No tags
            return DeleteResult.FAMILY_VERSION_DELETED;
          }
        }
      }
      if (familyVersionStamps.contains(Long.valueOf(timestamp))) {
        if (visibilityTagsDeleteFamilyVersion != null) {
          if (!visibilityTagsDeleteFamilyVersion.isEmpty()) {
            for (int i = 0; i < visibilityTagsDeleteFamilyVersion.size(); i++) {
              // visibilityTagsDeleteFamilyVersion is ArrayList
              Triple<List<Tag>, Byte, Long> triple = visibilityTagsDeleteFamilyVersion.get(i);
              if (timestamp == triple.getThird()) {
                List<Tag> putVisTags = new ArrayList<>();
                Byte putCellVisTagsFormat = VisibilityUtils.extractVisibilityTags(cell, putVisTags);
                boolean matchFound = VisibilityLabelServiceManager.getInstance()
                  .getVisibilityLabelService().matchVisibility(putVisTags, putCellVisTagsFormat,
                    triple.getFirst(), triple.getSecond());
                if (matchFound) {
                  return DeleteResult.FAMILY_VERSION_DELETED;
                }
              }
            }
          } else {
            if (!VisibilityUtils.isVisibilityTagsPresent(cell)) {
              // No tags
              return DeleteResult.FAMILY_VERSION_DELETED;
            }
          }
        } else {
          if (!VisibilityUtils.isVisibilityTagsPresent(cell)) {
            // No tags
            return DeleteResult.FAMILY_VERSION_DELETED;
          }
        }
      }
      if (deleteCell != null) {
        int ret = comparator.compareQualifiers(cell, deleteCell);
        if (ret == 0) {
          if (deleteType == KeyValue.Type.DeleteColumn.getCode()) {
            if (visibilityTagsDeleteColumns != null) {
              if (!visibilityTagsDeleteColumns.isEmpty()) {
                for (Pair<List<Tag>, Byte> tags : visibilityTagsDeleteColumns) {
                  List<Tag> putVisTags = new ArrayList<>();
                  Byte putCellVisTagsFormat =
                    VisibilityUtils.extractVisibilityTags(cell, putVisTags);
                  boolean matchFound = VisibilityLabelServiceManager.getInstance()
                    .getVisibilityLabelService().matchVisibility(putVisTags, putCellVisTagsFormat,
                      tags.getFirst(), tags.getSecond());
                  if (matchFound) {
                    return DeleteResult.VERSION_DELETED;
                  }
                }
              } else {
                if (!VisibilityUtils.isVisibilityTagsPresent(cell)) {
                  // No tags
                  return DeleteResult.VERSION_DELETED;
                }
              }
            } else {
              if (!VisibilityUtils.isVisibilityTagsPresent(cell)) {
                // No tags
                return DeleteResult.VERSION_DELETED;
              }
            }
          }
          // Delete (aka DeleteVersion)
          // If the timestamp is the same, keep this one
          if (timestamp == deleteTimestamp) {
            if (visiblityTagsDeleteColumnVersion != null) {
              if (!visiblityTagsDeleteColumnVersion.isEmpty()) {
                for (Pair<List<Tag>, Byte> tags : visiblityTagsDeleteColumnVersion) {
                  List<Tag> putVisTags = new ArrayList<>();
                  Byte putCellVisTagsFormat =
                    VisibilityUtils.extractVisibilityTags(cell, putVisTags);
                  boolean matchFound = VisibilityLabelServiceManager.getInstance()
                    .getVisibilityLabelService().matchVisibility(putVisTags, putCellVisTagsFormat,
                      tags.getFirst(), tags.getSecond());
                  if (matchFound) {
                    return DeleteResult.VERSION_DELETED;
                  }
                }
              } else {
                if (!VisibilityUtils.isVisibilityTagsPresent(cell)) {
                  // No tags
                  return DeleteResult.VERSION_DELETED;
                }
              }
            } else {
              if (!VisibilityUtils.isVisibilityTagsPresent(cell)) {
                // No tags
                return DeleteResult.VERSION_DELETED;
              }
            }
          }
        } else if (ret > 0) {
          // Next column case.
          deleteCell = null;
          // Can nullify this because we are moving to the next column
          visibilityTagsDeleteColumns = null;
          visiblityTagsDeleteColumnVersion = null;
        } else {
          throw new IllegalStateException("isDeleted failed: deleteBuffer="
            + Bytes.toStringBinary(deleteCell.getQualifierArray(), deleteCell.getQualifierOffset(),
              deleteCell.getQualifierLength())
            + ", qualifier="
            + Bytes.toStringBinary(cell.getQualifierArray(), cell.getQualifierOffset(),
              cell.getQualifierLength())
            + ", timestamp=" + timestamp + ", comparison result: " + ret);
        }
      }
    } catch (IOException e) {
      LOG.error("Error in isDeleted() check! Will treat cell as not deleted", e);
    }
    return DeleteResult.NOT_DELETED;
  }
This tag is used for the DELETE cell which has no visibility label.
hbase-server/src/main/java/org/apache/hadoop/hbase/security/visibility/VisibilityScanDeleteTracker.java