You can click Upload a File and see what is allowed. IFAIK there has never been any malware on this site and admins and mods would take it down if any was found.Is there not a ban on zip files? Many sites do not allow uploads of them, due to malware issues.
Ooook..xls and .xlxs EXCEL spreadsheet files?
Maximum attachment size into a post was 5MB, have changed to 10MB just now.