| xfdl | XFDL Document |
| xfo | XSL-FO Formatted Form |
| xfp | Microsoft InfoPath Property Promotion |
| xgl | XGL 3D CAD Model |
| xgml | Graph Modeling Language XML |
| xgz | MegaBitz XGL Vector Drawing |
| xhf | XHeader Document |
| xht | XHTML Document |
| xhtm | XHTML Document |
| xhtml | XHTML Document |
| xig | XML Instance Generator Document |
| xl | Microsoft Excel Worksheet |
| xla | Microsoft Excel VBA Add-in |
| xla8 | Microsoft Excel 98 for Mac Add-in |
| xlam | Microsoft Excel 2007 VBA Add-in |
| xlax | Microsoft Excel 2007 VBA Add-in |
| xlb | Microsoft Excel toolbar Setup |
| xlc | Microsoft Excel Chart File |
| xlc3 | Microsoft Excel 3 for Mac Chart Document |
| xlc4 | Microsoft Excel 4 for Mac Chart Document |
| xlcsv | Microsoft Excel Comma-Separated Values Document |
| xld | Microsoft Excel Dialogue |
| xlf | XLIFF Document |
| xli | XLIFF Document |
| xlif | XLIFF Document |
| xliff | XLIFF Document |
| xline | XLine Mind Map Document |
| xlk | Microsoft Excel XLS Backup |
| xll | Microsoft Excel Add-in |
| xlm | Microsoft Excel Macro Definition |
