#_X_EXTENSIONS

.X    DirectX 3D object file.
.X    DirectX model file.
.X    X3D2 mesh map (UNGSoft's Visual Terrain Maker).
.X16  Xtras for 16-bit Windows Macromedia/Authorware applications (Macromedia Authorware 6).
.X2I  Settings file (XPS2Images Converter).
.X32  Xtras for 32-bit Windows Macromedia/Authorware applications (Macromedia Authorware 6, Macromedia Freehand, etcetera).
.X3D  Xara3D file (Xara3D).
.X64  VICE variation of the Commodore 1541/D64 disk drive image file (VICE).
.XAML XAML markup file (Corel Word Perfect Office X6, Windows .NET Framework applications).
.XAUTOPF XML Auto Playlist File (Steven Mayall's MusicBee).
.XBA  StarOffice Basic language program (Sun's StarOffice and OpenOffice supporting Office suites).
.XBAP XAML Browser Application file (Corel Word Perfect Office X6).
.XBM  X BitMap format image (Many graphics applications).
.XCF  Native image file format of GIMP (GNU Image Manipulation Tool and other image applications).
.XDR  XML Data Reduced schema file (Microsoft VisualStudio).
.XEN  Xenu Link Sleuth file (Tilman Hausherr's Xenu Link Sleuth 1.x).
.XFDF Forms Document File (Adobe Acrobat and compatible applications).
.XFM  Transforms files (Syntrillium Cool Edit Pro).
.XFR  XFrog 3D file (Lintermann und Deussen's/Greenworks' XFrog 3).
.XFX  OpenFX file (OpenFX Animator).
.XGML XML Graph Markup Language file (yWorks' yEd Graph Editor).
.XI   Extended Instrument file = Fastracker 2 format (FruityLoops, Orangator, and other audio/sampler/tracker applications).
.XIF  Tag Image File Format file = TIFF file (Many graphics applications).
.XKEY Product registration Key file (Analinx Duplicatch).
.XLA  Microsoft Excel Add-in file (Microsoft Excel).
.XLB  Microsoft Excel Toolbar configuration file (Microsoft Excel).
.XLC  Microsoft Excel Chart file (Microsoft Excel).
.XLK  Microsoft Excel Backup file (Microsoft Excel).
.XLL  Microsoft Excel XLL Add-in file = an Excel library file (Microsoft Excel).
.XLM  Microsoft Excel Macros file (Microsoft Excel).
.XLP  Xleaner Plug-in file (More Than A Cleaner's Xleaner).
.XLS  Microsoft Excel format spreadsheet/worksheet file (Most Office application suites).
.XLSHTML Microsoft Excel HTML Document file (Microsoft Excel).
.XLT  Microsoft Excel spreadsheet Template file (Microsoft Excel and many other Office application suites).
.XLW  Microsoft Excel Worskspace file (Microsoft Excel).
.XM   FastTracker II Module audio file (Many tracker/audio applications).
.XML  Extensible Markup Language file (Many applications).
.XML~ Temporary XML file (Corel's CorelDRAW X6).
.XMO  Movie driver file (Macromedia Authorware 6).
.XMP  XML Presets file (PhotoMatrixPro).
.XMR  XMedia Recode settings file (XMedia Recode 3).
.XMT  XML-based Template file (QuarkXPress Passport).
.XNEWSRC Usenet newsgroups and header indices (Xnews Usenet newsreader).
.XNK  Exchange shortcut Link file (Microsoft Outlook/Outlook Express).
.XNT  QuarkXPress Extension file (QuarkXPress Passport, Quark CopyDesk and other Quark products).
.XPI  Plug-in extension file = ZIP archive (Mozilla Firefox).
.XPL  XingMP3 Playlist file (Xing Technology's Xing MP3 Player).
.XPM  Bitmap image format from X-Window systems supporting up to 256 colors.
.XPM  Unix icon file (Hagen Wieshofer's Icon Edit Pro).
.XPM  X PixMap format image (Many graphics applications).
.XSL  Extensible Stylesheet Language file = an XML-based variant of a cascading style sheet/CSS file (Many applications).
.XSLT Extensible Stylesheet Language Transformation file (Microsoft VisualStudio and other applications).
.XSPF XML Shareable Playlist Format file (VLCTeam's VideoLAN client, Steven Mayall's MusicBee and many other media applications).
.XTC  XTrackCAD Tracks file (Timothy M Shead's K-3D 0.8).
.XTG  QuarkXPress Tags file (QuarkXPress, Quark CopyDesk and other Quark products).
.XTODVD ConvertXtoDVD project file (VSO-Software's ConvertXtoDVD).
.XTS  QuarkXPress XTension Set file (QuarkXPress Passport).
.XWV  Maelstrom synthesizer device patch file (Propellerhead's Reason).
.XXT  QuarkXPress XTension file (QuarkXPress Passport).
.XY   XyWrite format document (XYWrite III Plus and other word processors).