The APEX_DATA_PARSER. GET_XLSX_WORKSHEETS function should also return the visibility state of the sheet (visible, hidden, veryHidden).

I occasionally get asked to deal with a .xlsx file where the sheet of interest is the first or only visible sheet, but there are other, hidden sheets in the workbook. Without this column returned by the function, there's no way to tell what the “first visible sheet” is.

In the OOXML structure, this is the “state” attribute in the <sheet> elements in xl/workbook.xml.