| xsm | Sybase PowerDesigner XML Model |
| xsn | xyAlgebra Data |
| xso | XKeyBrew Menu Data |
| xsp | MAPublisher XSP Data Source |
| xsprl | X-Setup Pro Data |
| xsprla | X-Setup Pro Data |
| xsr | Bentley GEOPAK XS List Report |
| xsr | Tekla Structures FabTrol Report |
| xss | Microsoft SharePoint WorkSpace Groove Database |
| xssz | Oracle BI Publisher Style Template |
| xstb | TextBridge Pro Data |
| xstk | xStarter Task Data |
| xsu | UNICOM Sample User XML Data |
| xsvf | Xilinx Serial Vector Format |
| xsz | ZynAddSubFX Standalone Scale File |
| xtabs | CFi Explorer Tabset Data |
| xtb | LocoScript External Translation Table |
| xtd | LabChip XT Data |
| xte | LabChip XTe Data |
| xterme | Winstep Xtreme Theme |
| xtf | LS-DYNA Extra Time History Database |
| xtic | ActivInspire Ticker Data |
| xtk | X-Ray Toolkit Metadata |
| xtm | XtremSplit Data |
| xtmp | Avid Xpress Pro Template |
| xtp | XTree Data |
| xtp | XTrkCAD Layout |
| xtp2 | Microsoft InfoPath Form Template Part |
| xtpl | XER Manager Template |
| xtr | RealArcade Compressed Data |
| xtr | XTrkCad Demo |
| xtreme | Winstep Xtreme Theme Pack |
| xtrl | XTND Translator Data |
| xts | IMPS Data |
| xtt | X TimeTable Data |
