Man pages matching name spreadsheet::readsxc in section 3pm:

Spreadsheet::ReadSXC.3pm.en	debian 10 / libspreadsheet-readsxc-perl
Spreadsheet::ReadSXC.3pm.en	debian 11 / libspreadsheet-readsxc-perl
Spreadsheet::ReadSXC.3pm.en	debian 12 / libspreadsheet-readsxc-perl