It's appropriate to name this class singular.

Since each instance refers to a single file format, while its array
instance holds multiple instances of this structure.

sc/qa/unit/filters-test.cxx

@@ -78,11 +78,11 @@ const int indeterminate = 2;
 
 namespace {
 
-struct FileFormats {
+struct FileFormat {
     const char* pName; const char* pFilterName; const char* pTypeName; sal_uLong nFormatType;
 };
 
-FileFormats aFileFormats[] = {
+FileFormat aFileFormats[] = {
     { "ods" , "calc8", "", ODS_FORMAT_TYPE },
     { "xls" , "MS Excel 97", "calc_MS_EXCEL_97", XLS_FORMAT_TYPE },
     { "xlsx", "Calc MS Excel 2007 XML" , "MS Excel 2007 XML", XLSX_FORMAT_TYPE }