2.4.695 BrtKnownFonts
The BrtKnownFonts record specifies that typographical descent information is stored in the workbook. This record MUST be present if and only if a BrtRwDescent (section 2.4.780) record is stored for every non-empty row in all Macro Sheet (section 2.1.7.32) and Worksheet parts (section 2.1.7.62) (see section 2.2.1 for more information) in the workbook, and if and only if a BrtWsFmtInfoEx14 (section 2.4.860) record is stored in all Macro Sheet and Worksheet parts in the workbook.