| wfm | dBASE IV Form Data |
| wfo | Delphi Runimage File |
| wfs | Windows Script File |
| wgp | WinDev Internal Compilation Data |
| whl | Python Wheel Package |
| whs | WinHex Script |
| whteko | WebHub Marked-up HTML Data |
| wic | wIntegrate Configuration Data |
| wid | Visual Studio Widget Data |
| widget | HybridJava Widget |
| wiki | Wikitext Source Code |
| win | GameMaker Studio Game Asset Package |
| win | Visual FoxPro Window File |
| winmd | Microsoft Windows Metadata |
| winsqlscript | WinSQL Script |
| wip | wIntegrate Installation Process Data |
| wiq | Visual Studio Work Item Query |
| wis | Rocket wIntegrate Script |
| wix | wIntegrate Compiled Script |
| wixlib | WiX Library |
| wixmsp | WiX XML Patch File |
| wixmst | WiX Transform File |
| wixobj | WiX Object File |
| wixout | WiX XML Output File |
| wixpdb | WiX Debug File |
| wixproj | WiX Toolset Project File |
| wk | HiSilicon NNIE WK Data |
| wkf | KF Webserver Script |
| wl | WinDev WLangage Source Code |
| wli | WL Intermediate Data |
| wlmi | WLM Intermediate Data |
| wln | Novell Localisation Workbench Workspace |
| wlog | WinDev Runtime Log |
| wlx | FileMaker Pro Plug-in |
| wmb | 3D Gamestudio Compiled Map |
| wmem | WinDev Memory Dump Data |
| wmfx | Wild Magic 5 Compiled FX |
| wmk | WebMake Documentation Source Code |
| wmls | WMLScript File |
| wmlsc | Compiled WMLScript |
| wmvf | Wild Magic 5 Visual Data |
| wo | DataFlex Web Object |
| woa | WebObjects Application |
| wod | WebObjects Declaration |
| woo | WebObjects Object |
| work | Mach-O Framework Data |
| workbook | Xamarin Workbook Data |
| workspace | Code::Blocks Workspace |
| wpa | WinDev Action Plan Data |
| wpc | WinDev Color Palette Data |
| wpf | WinDev Performance Profiler Data |
| wpj | Watcom C Project |
| wpss | IBM WebSphere Portal Server Settings Data |
| wpu | WinG User and Machine Specific Data |
| wpw | WinDev Mobile Window Data |
| wrc | WinDev Class References Data |
| wre | WinDev Report References Data |
| wrg | WinDev Procedure Set References Data |
| wrk | WinDev Component References Data |
| wrn | Eclipse WRN Data |
| wrp | WinDev Project References Data |
| wrr | WinDev Request References Data |
| wrw | WinDev Window References Data |
| wrx | Progress OpenEdge ActiveX Properties |
| ws | Microsoft Windows Script |
| ws4d | Web Server 4D Custom Web Page |
| wscript | Waf Wscript |
| wsct | WinDev Test Scenario |
| wsd | RoboSoft Script |
| wsdd | Axis Web Service Deployment Descriptor |
| wse | Wise Package Studio Script |
| wsi | Wise Package Studio Installer Package |
| wsil | Web Services Inspection Language Data |
| wsm | WinDev Modeling Graph Data |
| wsm | Wise Package Studio Merge Module |
| wsmdi | Visual Studio Test List Data |
| wsp | Visual C++ Workspace Data |
| wsrc | WAIS Source File |
| wssp | CommuniGate Pro Web Server-Side Programming Data |
| wte | WinDev Report Template |
| wwf | WebDev Installation Description |
| wwh | WebDev Frameset Data |
| wwn | WebDev Browser Procedures |
| wwt | WebDev Page Template |
| wx | WinDev External Configuration Data |
| wxb | wxBasic Source Code |
| wxf | WinDev Installation Temporary Data |
| wxf | WinSQL Scheduled Task Script |
| wxform | wxWidgets Form Data |
| wxi | WiX Include File |
| wxl | WiX Localization File |
| wxr | wxWidgets Resource Data |
| wxres | WinDev Automatic Test Results |
| wxs | Code::Blocks XML Data |
| wxs | WiX Source File |
| wxt | WinDev Automatic Test |
| x | Cygwin LD-Script Linker Data |
| x | Microsoft DirectX D3D Object |
| x | XBLite Source Code |
| xact | XactCommerce XactScript |
| xadl | XPLATFORM Application Program Definition |
| xal | Exient XGS Asset List Data |
| xal | Open XAL Configuration |
| xamlx | Visual Studio Workflow Service |
| xap | XACT Project File |
| xat | XAT Template |
| xbl | Extensible Binding Language File |
| xbml | SAP Business One Studio Workflow Process Data |
| xbw | SUP Hybrid Web Container Workflow |
| xcappdata | Xcode App Data |
| xcarchive | Xcode Archive |
| xcb | Visual C++ Command Bar Data |
| xcconfig | Xcode Configuration Settings |
| xccrashpoint | Xcode Crash Point Data |
| xcdatamodel | Xcode Core Data Model |
| xcdatamodeld | Xcode Core Data Model |
| xcent | Xcode Entitlements Data |
| xcl | IAR System Linker Command File |
| xclangspec | Xcode Language Specification Data |
| xcmd | HyperCard External Commands |
| xcodeplugin | Xcode Plug-in |
| xcof | Mac OS Object Library |
| xcp | XLNT Script |
| xcplugin | Xcode Plug-in |
| xcplugindata | Xcode Plug-in Data |
| xcscheme | Xcode Scheme Document |
| xcsnapshots | Xcode Snapshots Data |
| xcss | RichFaces XCSS File |
| xct | Xilinx PARTGen Partlist File |
| xct | XVI32 Conversion File |
| xcuserstate | Xcode User State Data |
| xdb | Sybase PowerDesigner Database Definition |
| xdd | WinDev Internal Analysis Data |
| xdf | Dyalog APL Data |
| xdf | Extensible Data Format File |
| xdf | ProWorx NXT Extended Memory Data File |
| xdf | XCAP Diff Data |
| xdfl | eXtensible Data Flow Language Document |
| xdfz | Compressed Extensible Data Format File |
| xdim | MCS Markup Editor XDIME Document |
| xdk | XML Development Kit Project |
| xdoclet | JBoss XDoclet Reference Data |
| xds | DS Game Maker Project |
| xds | OpenGL Performer Script |
| xdt | Xscript Data File |
| xdw | Dyalog APL Workspace Data |
| xfd | Microfocus Acu4GL Extended Description |
| xfdl | XPLATFORM Screen Form Definition |
| xfl | Adobe Flash Exchange Data |
| xgdw | GDevelop Extension |
| xgf | Xgridfit Program |
| xgm | Exient XGS Model Data |
| xgr | GraphEdit Filter Graph Markup Language |
| xgt | Exient XGS Texture Data |
| xib | Apple Interface Builder Development-Time Resources |
| xil | Xilize Markup Source |
| xilinc | Xilize Include |
| xilize | Xilize Configuration Data |
| xin | OmniMark Include File |
| xiw | CSR µEnergy SDK Workspace |
| xjb | OEPE JAXB Wizard Bindings Data |
| xje | XJEase Source Code |
| xlc | Exient XGS Locale Data |
| xlist | MASM XLIST Data |
| xmap | CodeWarrior Linker Map Data |
| xmat | Exient XGS Shader Material Data |
| xmcf | FileMaker Pro Custom Function Data |
| xmf | Milinta APL Mainframe SAM Data |
| xmla | XML for Analysis File |
| xmlc | ASP.NET Compiled XML |
| xmljet | Eclipse JET XML Template |
| xmlo | FileMaker Pro Layout Object Data |
| xmta | Visual Studio Design-Time Attribute Data |
| xmw | Milinta APL Mainframe SAM Workspace |
| xn | Cygwin LD-Script Data |
| xnb | XNA Game Studio Binary Package |
| xnd | exNode Download Data |
| xnml | NML Language Extension |
| xob | WeintekHMI EasyBuilder 8000 XOB File |
| xojo_binary_menu | Xojo Binary Menu Data |
| xojo_binary_project | Xojo Binary Project |
| xojo_binary_toolbar | Xojo Binary Toolbar Data |
| xojo_binary_window | Xojo Binary Window Data |
| xojo_menu | Xojo Menu Data |
| xojo_project | Xojo Project |
| xojo_toolbar | Xojo Toolbar Data |
| xojo_window | Xojo Window Data |
| xojo_xml_menu | Xojo XML Menu Data |
| xojo_xml_project | Xojo XML Project |
| xojo_xml_toolbar | Xojo XML Toolbar Data |
| xojo_xml_window | Xojo XML Window Data |
| xol | Sybase PowerDesigner Object Language Data |
| xoml | Microsoft Visual Studio Windows Workflow |
| xpb | XPB! Basic Source Code |
| xpf | Milinta APL AplX Data |
| xpi | Xilinx ISE PAR Summary Data |
| xpk | Xscript Package |
| xpp | X++ Source Code |
| xpr | Oxygen XML Editor Project |
| xpw | Milinta APL AplX Workspace |
| xpz | GeneXus Object |
| xq | XQuery Language Source Code |
| xql | XML Query Language |
| xqm | Oxygen XML Editor XQuery Module |
| xqu | XQuery Update Data |
| xrc | wxWidgets XML Based Resource |
| xrd | XRK Data File |
| xrg | Xscript Registry Data |
| xrm | XrmToolkit XRM Data |
| xrmcache | XrmToolkit XRM Cache |
| xrmsuo | XrmToolkit CRM Credentials Data |
| xs | Perl h2xs XSUB Data |
| xsc | Dataset Designer Internal Data |
| xsc | Xscript Script |
| xsc | XVI32 Script |
| xsd | Altova XMLSpy XMD Schema Definition Data |
| xsf | Milinta APL APL+Win Data |
| xso | Expresso Project |
| xsql | Oracle XSQL Servlet Server Side File |
| xss | Dataset Designer Surface Data |
| xst | IBM WebSphere Query Template |
| xsu | Fortran 77 Library |
| xsw | Milnta APL Transfer Function Data |
| xsy | Unity Pro Exported Variables |
| xsym | CodeWarrior xSYM File |
| xt | Xdebug Trace Output |
| xtf | Xilinx ISE Netlist Data |
| xtml | XML4web HTML Document |
| xuf | Milinta APL Unix SAX Data |
| xul | XML User Interface Language File |
| xuw | Milinta APL Unix SAX Workspace |
| xyz | RPG Maker Graphic Data |
| y | Yacc Source |
| yab | Yabasic Source Code |
| yajl | YAJL Script |
| yang | YumaPro YANG Module |
| yaws | Yaws Server Dynamic Page |
| ygl | YAGL Script |
| yin | YumaPro YIN Module |
| yml2 | YML 2 Script |
| yo | Y86 Assembler Object |
| yobj | Yukes 3D Object |
| ys | Y86 Assembler Source Code |
| ysp | BYOB Sprite |
| yxx | GNU Bison Source Code |
| yy | GNU Bison Parser |
| z | Zero Compiler Header |
| zanebug | Zanebug Data |
| zasm | Zero Compiler Assembly Source Code |
| zbi | Zeus IDE Special Tags Data |