private static String findWorkbookEntry(DirectoryNode root) {
        for (String workbookDirEntryName : InternalWorkbook.WORKBOOK_DIR_ENTRY_NAMES) {
            if (root.hasEntry(workbookDirEntryName)) {
                return workbookDirEntryName;
            }
        }
        return null;
    }
Looks for one of the variant names for the workbook entry;
returns null if not found.

@param root directory root to search
@return workbook entry or null
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/ExcelExtractor.java