| 1 | $ | Microsoft Corporation | Visual Basic Symbol |
| 2 | 3 | N/A | Unix Section 3 Manual Page |
| 3 | 30 | N/A | Generic |
| 4 | 3DMARK-RESULT | Futuremark | 3DMark Results File |
| 5 | 3DR | Futuremark | 3DMark Results Format |
|
| 6 | 3PM.8 | Apple, Inc. | Apple MAC OS X |
| 7 | 47 | N/A | FreeBSD |
| 8 | 5 | N/A | FreeBSD |
| 9 | 5A | N/A | Linux |
| 10 | 5VW | InfoVista | 5Views Packet Capture |
| 11 | 8 | IBM | IBM Embedded ViaVoice Voice Type Languages Scripts Data |
| 12 | 85D | N/A | TI-85 graphic database |
| 13 | 85K | N/A | Generic |
| 14 | 85M | N/A | TI-85 data |
| 15 | 85N | N/A | TI-85 data |
| 16 | 85P | N/A | Generic |
| 17 | 85R | N/A | TI-85 data |
| 18 | 86Y | N/A | TI-86 data |
| 19 | 89Y | N/A | Generic |
| 20 | 8CG | N/A | TI-84 Plus data |
| 21 | 8PU | N/A | Generic |
| 22 | 92K | N/A | Generic |
| 23 | 92U | N/A | TI-92 update data |
| 24 | 9XY | N/A | Generic |
| 25 | ?RS | N/A | Corel WordPerfect support file |
| 26 | AB1 | N/A | DNA Electropherogram Format |
| 27 | AB2 | Broderbund | Print Shop Address Book Format |
| 28 | ABCDDB | Apple, Inc. | Apple Address Book Database |
| 29 | ABCDG | Apple, Inc. | Apple AddessBook |
| 30 | ABCDP | Apple, Inc. | Address Book Card Data |
| 31 | ABL | Xilinx, Inc. | ABEL Hardware Description Language |
| 32 | ACBL | Adobe Systems | Adobe Color Book Legacy Format |
| 33 | ACC | FKJ Software | Quicken 2002 Internet Common Format |
| 34 | ACCDA | Microsoft | Access Add-in Format |
| 35 | ACCDB | Microsoft | Access 2007 Database Format |
| 36 | ACCDC | Microsoft | Microsoft Access Signed Package |
| 37 | ACCDE | Microsoft | Access Execute Only Database |
| 38 | ACCDP | Microsoft Corporation | Microsoft Access 2007/2010 Project |
| 39 | ACCDR | Microsoft | Access Runtime Application |
| 40 | ACCDT | Microsoft | Microsoft Access Database Template |
| 41 | ACCDU | Microsoft | Access Add-in Format |
| 42 | ACFF | N/A | Generic |
| 43 | ACRODATA | Adobe Systems | Acrobat Data Format |
| 44 | ADCP | Adobe Systems | Adobe Device Central Project Format |
| 45 | ADE | Microsoft | Access Project Extension |
| 46 | ADOBEBRIDGE | Adobe Systems Incorporated | Adobe Bridge |
| 47 | ADPCM | N/A | ADPCM audio |
| 48 | ADPP | Adobe Systems | Adobe Device Profile Package |
| 49 | ADTG | N/A | Advanced Data TableGram |
| 50 | AETX | Adobe Systems | After Effects XML Project Template |
| 51 | AGWL | Distributed and Parallel Systems - University of Innsbruck | Abstract Grid Workflow Language |
| 52 | AHU | Adobe Systems | Adobe Photoshop HSL Format |
| 53 | AKF | Adobe Systems Incorporated | Adobe Acrobat Key |
| 54 | ALBUM | N/A | Thumbnail Cache |
| 55 | ALT | Microsoft | Dynamics AX Temporary Format |
| 56 | ALV | Adobe Systems | Adobe Photoshop Levels Format |
| 57 | AMEPROJ | N/A | Generic |
| 58 | AMEPROJCC | N/A | Generic |
| 59 | AMES | N/A | NASA Ames data exchange format |
| 60 | ANR | DeLorme | DeLorme Street Atlas Route |
| 61 | AOL | AOL | America On-line Related Format |
| 62 | AP0 | Microsoft Corporation | Microsoft Windows APW_data |
| 63 | APDB | Apple, Inc. | Apple Aperture Library |
| 64 | APDETECTED | Apple, Inc. | Apple IPhoto |
| 65 | APFOLDER | N/A | Aperture Folder |
| 66 | APH | Ability Plus Software | Ability Photoalbum Album Database Format |
| 67 | APKG | Damien Elmes | Exported Anki Flashcard Deck |
| 68 | APLMODEL | Apple, Inc. | Apple ICal |
| 69 | APMASTER | N/A | Aperture Master |
| 70 | APPLACE | N/A | Apple Photos data |
| 71 | APVERSION | N/A | Aperture Version info |
| 72 | APVOLUME | N/A | Apple Photos data |
| 73 | APX | Embarcadero Technologies | Borland C++ Appexpert Database Format |
| 74 | ART50 | BERNINA International AG | BERNINA V5.0 Embroidery Software Designs |
| 75 | ART60 | BERNINA International AG | BERNINA V6.0 Embroidery Software Designs |
| 76 | ASD | Microsoft | Word AutoSave Format |
| 77 | ATT | N/A | Web Form Data Format |
| 78 | AUM | Adobe Systems Incorporated | Adobe Update Manager Data |
| 79 | AVG | AVG Technologies (Grisoft) | AVG Antivirus Virus Database |
| 80 | AVGDX | AVG Technologies | AVG Diagnostics Format |
| 81 | AVJ | Avira Operations | Avira Anti-Vir Job Format |
| 82 | AVM | AVG Technologies (Grisoft) | AVG Incremental Persistent |
| 83 | B | IBM | IBM Lotus Applause Batch List Format |
| 84 | B4P | N/A | Native Instruments B4 II preset |
| 85 | BAC | Avantrix | Backup Format |
| 86 | BAROC | N/A | IBM Tivoli console adapter description |
| 87 | BBLX | Rick Meyers | E-Sword Bible |
| 88 | BDC | Babylon | Babylon Dictionary Format |
| 89 | BDIC | Google | Chrome Dictionary Format |
| 90 | BDR | Microsoft | Exchange Non-Delivery Report Body Format |
| 91 | BDSGROUP | Embarcadero Technologies, Inc. | BDS Project Group |
| 92 | BGL | Microsoft | Flight Simulator Scenery Format |
| 93 | BKY | MIT | Bookkey Bookmark/keyword Data |
| 94 | BLA | Adobe Systems Incorporated | Adobe Black Colour Separation |
| 95 | BLIF | N/A | Berkeley Logic Interchange Format |
| 96 | BPMN | KAISHA-Tec Co. Ltd | Avantage Template |
| 97 | BRN | BrainStorm Software | BrainStorm Data Format |
| 98 | BSDESIGN | Zine | Bootstrap Studio Website Design |
| 99 | BST | N/A | BibTeX Style Document |
| 100 | BSWX | Microsoft Corporation | Microsoft Office PerformancePoint Server Database |
| 101 | BTH | Jeppesen Marine, Inc. | Bathy Recorder Data |
| 102 | BTK | Procedimientos-Uno, S.L. | CLwin Tekton Database |
| 103 | BTKEY | BitTorrent, Inc. | BitTorrent License Key |
| 104 | BVY | N/A | Breevy text snippet |
| 105 | BWT | VSO Software | BlindWrite 4 Disk Image |
| 106 | BYU | BYU | Movie.BYU Geometry Format |
| 107 | CA | N/A | Initial Telnet Cache |
| 108 | CACTION | Apple | Automator Converter Action |
| 109 | CAR | N/A | Car Explorer Data Format |
| 110 | CAS | Autodesk | Autodesk AutoCAD License Format |
| 111 | CBD | Corel Corporation | Corel WordPerfect Dictionary |
| 112 | CBO | Microsoft Corporation | Microsoft Interactive Training |
| 113 | CBPROJ | Embarcadero Technologies, Inc. | C++ Builder Project |
| 114 | CEDF | N/A | Ultra TC Editors Data File |
| 115 | CETRAINER | Cheat Engine | DBVM |
| 116 | CH6 | N/A | ZX-Paintbrush character |
| 117 | CH8 | N/A | Generic |
| 118 | CHI | Microsoft Corporation | Microsoft Help Index |
| 119 | CHK | Microsoft | ScanDisk Format Fragment |
| 120 | CIE | N/A | Generic |
| 121 | CLAM | Adobe Systems Incorporated | Adobe InDesign Dictionary |
| 122 | CLX | Adobe Systems | Standard Dictionary Format |
| 123 | CM5 | Sci-Ed | LexisNexis Case Analysis |
| 124 | CMT | N/A | Chinon ES-1000 Digital Camera Image Format |
| 125 | CMTX | Rick Meyers | E-Sword Commentary |
| 126 | CN | Procedimientos-Uno, S.L. | CNwin/MLwin Account |
| 127 | COF | Autodesk | AutoDesk Data Format |
| 128 | CONTENTS | Apple, Inc. | MAC OS X |
| 129 | CPAA | Adobe Systems | Captivate Shared Action File |
| 130 | CPF | IBM | Cognos Project Format |
| 131 | CPI | Sony | AVCHD Video Clip Information Format |
| 132 | CPUPROFILE | N/A | Google Chrome DevTools data |
| 133 | CRD | Microsoft | Windows CardSpace Format |
| 134 | CRS | Corel Corporation | Corel WordPerfect Conversion Resource Format |
| 135 | CRTX | Microsoft | Office 2007 Chart Template Format |
| 136 | CRV | Corel Corporation | CorelDRAW Corel PHOTO-PAINT 10 Custom Gradients Format |
| 137 | CSN | Adobe Systems | Adobe Code Snippet Document |
| 138 | CXML | Microsoft Corporation | Microsoft Silverlight Server Side Data |
| 139 | DAILY | N/A | Day log |
| 140 | DAQ | MathWorks, Inc. | Data Acquisition Toolbox |
| 141 | DATA | Appricon | Analysis Studio Offline Data Format |
| 142 | DBQ | Corel Corporation | Paradox Memo Format |
| 143 | DC3 | IMSI/Design | Medicine Image Format |
| 144 | DCT | N/A | Dictionary Format |
| 145 | DCT5 | Microsoft Corporation | Microsoft Word 5 For Mac Dictionary |
| 146 | DCTX | Microsoft Corporation | Microsoft Office IME Open Extended Dictionary |
| 147 | DDD | Adobe | Adobe Distiller Format |
| 148 | DDL | N/A | Data Definition Language Format |
| 149 | DEA | N/A | Generic |
| 150 | DEF | Elecbyte | Module-Definition Format |
| 151 | DESKSOFTLICENSE | N/A | DeskSoft License |
| 152 | DEVICEINFO | Apple | Device Record |
| 153 | DFU | Apple | IOS DFU Format |
| 154 | DIAGSESSION | Microsoft | Diagnostics Session File |
| 155 | DIC | N/A | Dictionary Format |
| 156 | DLL_NON_OPT | Adobe Systems Incorporated | Adobe |
| 157 | DLV4 | Dassault Systèmes S.A. | Catia |
| 158 | DMP | Microsoft | Windows Memory Dump |
| 159 | DNX | IBM | IBM Rational Software |
| 160 | DOC | Microsoft | Microsoft Word Document |
| 161 | DOCM | Microsoft | Word Open XML Macro-Enabled Document |
| 162 | DOCX | Microsoft | Microsoft Word Open XML Document |
| 163 | DONOTPRESENT | Apple, Inc. | Apple Mac OS X Time Machine Resource Fork |
| 164 | DOST | Sony Corporation | DoStudio Subtitle Format |
| 165 | DOT | Microsoft | Word Document Template |
| 166 | DOTM | Microsoft | Word Open XML Macro-Enabled Document Template |
| 167 | DOTX | Microsoft | Word Open XML Document Template |
| 168 | DRT | Cadence Design Systems, Inc. | PSpice Or PCB Designer Custom Derating |
| 169 | DRX | Adobe Systems Incorporated | Adobe Photoshop Tutorial |
| 170 | DTA | IWIS | Data Format |
| 171 | DTI | N/A | Fifa 2001 Data |
| 172 | DTL | Electronic Arts, Inc. | The Sims |
| 173 | DUO | Microsoft Corporation | Microsoft Access |
| 174 | DUP0 | Samsung Group | Samsung Kies Duplicate Media |
| 175 | DUP1 | Samsung Group | Samsung Kies Duplicate Media |
| 176 | DUP2 | Samsung Group | Samsung Kies Duplicate Media |
| 177 | DVDFAB6 | Fengtao Software Inc. | DVDFab Key |
| 178 | DXG | Duxbury Systems, Inc. | Duxbury Braille Translator |
| 179 | EAR | Oracle | Java Enterprise Archive Format |
| 180 | ECG | Neozap | ECG Electrocardiography |
| 181 | EDI | N/A | Electronic Data Interchange Format |
| 182 | EM | Adobe Systems | Encore Menu Template |
| 183 | EMBL | European Molecular Biology Laboratory | EMBL Sequence Data File |
| 184 | EMLXPART | N/A | Mail Message Attachment |
| 185 | EMULECOLLECTION | eMule | EMule Data Format |
| 186 | ENC2 | Samsung Group | Samsung Galaxy Firmware Update |
| 187 | ENEWS | N/A | Generic |
| 188 | ENL | Thomson Reuters | EndNote Library |
| 189 | ENV | Now Software | Adobe Dictionary Data Format |
| 190 | EQN | N/A | Corel WordPerfect Equation Format |
| 191 | ERX | N/A | ER Data Model |
| 192 | ESCO | Nokia Corporation | Nokia Lumia Windows Phone 7 Firmware |
| 193 | ESD | AutoData Systems | ExpertScan Survey Document Format |
| 194 | EXC | Microsoft | Microsoft Word Exclusion Dictionary Format |
| 195 | EXE_0002 | N/A | Microsoft Outlook Inbox Repair Tool update |
| 196 | F2G | N/A | GIGABYTE BIOS update |
| 197 | F3G | N/A | GIGABYTE BIOS update |
| 198 | F4F | Adobe Systems | Flash Video Fragment |
| 199 | F4G | N/A | GIGABYTE BIOS update |
| 200 | F5G | N/A | GIGABYTE BIOS update |
| 201 | F6G | N/A | GIGABYTE BIOS update |
| 202 | FA | N/A | FASTA Formatted Sequence Format |
| 203 | FASTA | N/A | FASTA Sequence Format |
| 204 | FASTQ | N/A | FASTQ format |
| 205 | FAVORITE | Apple, Inc. | Apple IDVD Favorite |
| 206 | FDL | Corel Corporation | Corel Paradox Secondary Index |
| 207 | FDRTEMPLATES | AGS Technik | FDRTools Template |
| 208 | FDSEQ | Dolphin Futures Limited | XPS Document Related Data |
| 209 | FEA | N/A | AFDKO Feature Definitions File |
| 210 | FFA | Microsoft | Find Fast Status Format |
| 211 | FFO | Microsoft | Find Fast Document Properties Cache |
| 212 | FFT | Microsoft | Find Fast Indexer Format |
| 213 | FFX | Microsoft | Find Fast Indexer Index Format |
| 214 | FILE | N/A | Generic Windows Format |
| 215 | FILELOC | Apple, Inc. | Apple Mac OS X Finder Internet Location |
| 216 | FIT | Garmin | Flexible Image Transport System Format |
| 217 | FL3 | Adobe Systems | Flash 3D Format |
| 218 | FLAT | N/A | Flat data file |
| 219 | FMK | GFI Software | FaxMaker |
| 220 | FNL | Microsoft Corporation | Microsoft Live Mesh |
| 221 | FNLF | Novation | Novation Automap License Format |
| 222 | FO | N/A | XSL-FO Form |
| 223 | FPC | Microsoft Corporation | FoxPro Catalog |
| 224 | FP_FOLDER_INFO | N/A | Microsoft SharePoint data |
| 225 | FQ | N/A | Generic |
| 226 | FRM | MySQL | MySQL Database Format |
| 227 | FRV | Microsoft Corporation | Microsoft FRx |
| 228 | FRX | Microsoft | Visual Basic Binary Form Format |
| 229 | FSL | Corel | Corel Paradox Compiled Form Format |
| 230 | FTPLOC | N/A | FTP Location |
| 231 | FXD | Microsoft Corporation | FoxPro FoxDoc Support |
| 232 | G | Corel | Corel Paradox Format |
| 233 | GAI | Adobe Systems Incorporated | Adobe SING Glyphlet Manager |
| 234 | GCF | Valve | Game Cache Format |
| 235 | GED | The LDS Church | GEDCOM Genealogy Data Format |
| 236 | GFF | Roche NimbleGen, Inc. | SignalMap Gene-Finding Format (GFF) Data |
| 237 | GFS | Microsoft Corporation | Microsoft SharePoint WorkSpace Groove Remote |
| 238 | GIFT | N/A | Generic |
| 239 | GLK | Microsoft Corporation | Microsoft SharePoint WorkSpace Groove Shortcut |
| 240 | GLOS | Microsoft Corporation | Microsoft Word For Mac Glossary |
| 241 | GLY | Microsoft | Word Glossary Format |
| 242 | GOLD | The GNOME Project | Gnome Desktop |
| 243 | GP3 | Arobas Music | Guitar Pro 3 Format |
| 244 | GROUPPROJ | Embarcadero Technologies | Delphi Project Group Format |
| 245 | GRV | Microsoft | Office Groove Format |
| 246 | GSHADER | N/A | Microsoft Visual Studio data |
| 247 | GSL | Siber Systems, Inc. | GoodSync Job List |
| 248 | GTI | Georgia Tech Research Corporation | STRUDL Input |
| 249 | H1H | Microsoft Corporation | Microsoft Windows Merged Hierarchy Help |
| 250 | H1W | Microsoft Corporation | Microsoft Windows Keyword Index |
| 251 | HANG | Apple, Inc. | Apple Mac OS X Terminal |
| 252 | HAR | Rick Meyers | E-Sword Harmony Resource |
| 253 | HARX | Rick Meyers | E-sword Harmony |
| 254 | HCKX | N/A | Generic |
| 255 | HCT | Symantec Corporation | Symantec LiveUpdate |
| 256 | HELP | Apple | Mac OS X Help Book |
| 257 | HEX | N/A | Hexadecimal Source Format |
| 258 | HKF | Microsoft Corporation | Microsoft.NET Framework |
| 259 | HMF | Tech Soft 3D | HOOPS Metafile |
| 260 | HMSD | N/A | Microsoft Dictionary |
| 261 | HOL | Microsoft | Outlook Holidays Format |
| 262 | HSHADER | N/A | Microsoft Visual Studio data |
| 263 | HSS | Adobe Systems Incorporated | Adobe Dreamweaver Snippet |
| 264 | HWL | Corel Corporation | Corel WordPerfect Shared Writing Tools 9.0 |
| 265 | HXD | Microsoft Corporation | Microsoft Help Validator |
| 266 | HXF | Microsoft Corporation | Microsoft Help Include |
| 267 | HXH | Microsoft Corporation | Microsoft Help Merged Hierarchy |
| 268 | HXQ | N/A | Microsoft Help merged query index file |
| 269 | HXR | Microsoft Corporation | Microsoft Help Data |
| 270 | HXT | Microsoft | Microsoft Help 2 Table Of Contents Format |
| 271 | HYC | Corel Corporation | Corel WordPerfect Data |
| 272 | HYD | Corel Corporation | Corel WordPerfect Hyphenation Dictionary |
| 273 | HYP | Adobe Systems | Dictionary Information Format |
| 274 | I | Microsoft | Visual Studio Intermediate Format |
| 275 | IAF | Microsoft | Outlook Internet Account Format |
| 276 | ICXS | Apple, Inc. | ITunes |
| 277 | ID | IBM | Lotus Notes User ID Format |
| 278 | IDEA | Adobe Systems | Adobe Ideas Document |
| 279 | IDPK | Adobe Systems | Adobe InDesign Package For GoLive Format |
| 280 | IDT | Microsoft | Windows Installer Database Text Archive Format |
| 281 | IES | Illuminating Engineering Society | IES Photometric Data Format |
| 282 | IFD | Fly Software | InForm Document |
| 283 | IIL | N/A | CleanSweep Installation Log |
| 284 | INDEX | The Eclipse Foundation | Eclipse Help Index |
| 285 | INDP | Adobe Systems | Adobe InDesign CS3 Package Format |
| 286 | INIX | Adobe Systems Incorporated | Adobe InDesign |
| 287 | INL | Microsoft | C++ Inline Format |
| 288 | INLK | Adobe Systems | Adobe InDesign Lock Format |
| 289 | INMS | Adobe Systems | Adobe InDesign Menu Set Format |
| 290 | INPUTPLUGIN | Apple, Inc. | Apple Mac OS X PluginIM Input Method |
| 291 | INSTALLLOG | Microsoft Corporation | Microsoft .NET Installation Log |
| 292 | IOS | N/A | Generic |
| 293 | IPSX | N/A | iPhone firmware update |
| 294 | IPUTILS | The GNOME Project | Gnome Desktop |
| 295 | ITDB | Apple | ITunes Database Format |
| 296 | ITL | Apple | ITunes Library Format |
| 297 | ITLP | Apple | ITunes LP Album Format |
| 298 | ITSS | N/A | Generic |
| 299 | ITXIB | Apple, Inc. | Apple ITunes Dump |
| 300 | IWB | SMART Technologies ULC | Common Format |
| 301 | JDB | Symantec | Symantec Endpoint Protection Update Format |
| 302 | JNL | Actian Corporation | Ingres Journal |
| 303 | KEYSTORE | Oracle Corporation | Java Keytool Key Database |
| 304 | KEYTAB | Apple, Inc. | Unix Kerberos Encrypted Key |
| 305 | KFG | Adobe Systems Incorporated | Adobe Acrobat Rule |
| 306 | KODI | N/A | Kodi update data |
| 307 | KSDS | Native Instruments, Inc. | Absynth Kore Patch Format |
| 308 | KVK | Tavultesoft | Keyman Desktop On Screen Keyboard |
| 309 | LACCDB | Microsoft | Microsoft Access Lock Format |
| 310 | LBX | Microsoft | FoxPro Label Format |
| 311 | LCN | Corel Corporation | Corel WordPerfect Dictionary Format |
| 312 | LCX | Cray Inc. | LC Model |
| 313 | LDB | Microsoft | Microsoft Access Lock Format |
| 314 | LDL | Corel Corporation | Corel Paradox Delivered Library |
| 315 | LEF | N/A | LEN Exchange Format |
| 316 | LEX | Adobe Systems | Adobe Linguistic Library Data Format |
| 317 | LGE | N/A | Generic |
| 318 | LGM | Microsoft Corporation | Microsoft Windows Application Log |
| 319 | LGZ | Microsoft Corporation | Windows Application Log |
| 320 | LICKEY | Online Media Technologies Ltd. | AVS4YOU License Key |
| 321 | LIF | Leica Microsystems | Leica Image Format |
| 322 | LM | Microsoft | Language Model File |
| 323 | LNG | Nullsoft | Language Application Support Format |
| 324 | LNM | Corel Corporation | Corel WordPerfect SGML Alias |
| 325 | LNST | Adobe Systems | Adobe InDesign Line Presets Format |
| 326 | LOCK_SYNC | Apple, Inc. | Synchronization Lock |
| 327 | LOGONXP | Stardock | LogonStudio Windows XP Logon Screen |
| 328 | LRS | N/A | Librie Reader Source Format |
| 329 | LSL | Corel Corporation | Corel Paradox Format |
| 330 | LSTX | Rick Meyers | E-Sword Verse List |
| 331 | LTL | DIAL GMBH | DIALux Luminaire Data |
| 332 | LWG | N/A | Microsoft .NET data |
| 333 | MAF | Microsoft | Microsoft Access Form Shortcut Format |
| 334 | MAM | Microsoft | Microsoft Access Macro |
| 335 | MAQ | Microsoft | Microsoft Access Query |
| 336 | MAR | Mozilla | Mozilla Archive |
| 337 | MAS | Microsoft | Microsoft Access Stored Procedures Format |
| 338 | MAT | Microsoft | Microsoft Access Table Shortcut Format |
| 339 | MAW | Microsoft | Access Data Access Page |
| 340 | MBDB | Apple, Inc. | Apple IOS Backup Manifest |
| 341 | MBDX | Apple, Inc. | Apple IOS Backup Manifest |
| 342 | MBX | Microsoft | Outlook Express Mailbox |
| 343 | MD5 | N/A | MD5 Checksum Format |
| 344 | MDA | Microsoft | Access Add-in |
| 345 | MDB | Microsoft | Microsoft Access Database |
| 346 | MDE | Microsoft | Compiled Access Add-in Format |
| 347 | MDT | Intergraph | GeoMedia Access Database Template |
| 348 | MDW | N/A | Access Workgroup Format |
| 349 | MDZ | N/A | Access Wizard Template |
| 350 | MEH | N/A | Adobe Acrobat language resource |
| 351 | MEM | N/A | FoxPro Variable Format |
| 352 | MEMX | N/A | Generic |
| 353 | MEQ | Corel Corporation | Corel WordPerfect Macro Editor Print Queue |
| 354 | MER | Corel Corporation | Corel WordPerfect Macro Editor Resident Area Format |
| 355 | MF4 | Vector Informatik GmbH | Version 4.0 Measurement Data Format |
| 356 | MIG | Microsoft | Windows Migration Backup Format |
| 357 | MLC | Microsoft | Microsoft Language Interface Pack |
| 358 | MLOCATE | The GNOME Project | Gnome Desktop |
| 359 | MNFT | N/A | Generic |
| 360 | MOF | Desktop Management Task Force | Managed Object Format |
| 361 | MOL | Symyx Technologies | MDL Molfile |
| 362 | MOZLZ4 | Mozilla | Compressed Firefox User Profile Data File |
| 363 | MPD | Microsoft | Microsoft Project Database |
| 364 | MPP | Microsoft | Microsoft Project Format |
| 365 | MPT | Microsoft | Microsoft Project Template |
| 366 | MQH | MetaQuotes Software Corp. | MetaTrader Trading Terminal |
| 367 | MRDB | N/A | Generic |
| 368 | MRES | N/A | Generic |
| 369 | MRXS | Carl Zeiss MicroImaging | MIRAX Virtual Slide Format |
| 370 | MSHXML | Microsoft Corporation | Microsoft XML Typedata |
| 371 | MSM | Microsoft | Windows Installer Merge Module |
| 372 | MSMESSAGESTORE | Microsoft Corporation | Windows Mail Message Information Database |
| 373 | MSO | Microsoft | Inline E-mail Attachment |
| 374 | MSPDI | N/A | Microsoft Project XML data interchange |
| 375 | MSWMM | Microsoft | Windows Movie Maker Project |
| 376 | MULIB | Adobe Systems Incorporated | Adobe Muse Exported Library |
| 377 | MVD2 | N/A | Generic |
| 378 | MVF | Autodesk, Inc. | AutoFlix Stop Frame |
| 379 | MXSD | IBM | IBM WebSphere Message Definition |
| 380 | MYI | Oracle | MySQL MyISAM Index Format |
| 381 | MYSQL | N/A | MySQL data |
| 382 | N | Nicolas Cannasse | Neko Bytecode Format |
| 383 | N88 | Apple, Inc. | Apple IOS Kernel Cache |
| 384 | NA2 | Mozilla | Netscape Address Book Format |
| 385 | NB0 | N/A | Google Android Compiled ROM Format |
| 386 | NBV | N/A | Generic |
| 387 | NC | CNC Software | Unidata Network Common Data Form Format |
| 388 | NCH | Microsoft | Outlook Express Folder Format |
| 389 | NDM | Activision | Enemy Territory Quake Wars Demo |
| 390 | NDX | N/A | DBASE Index Format |
| 391 | NETKIT | The GNOME Project | Gnome Desktop |
| 392 | NEU | Parametric Technology | Pro/ENGINEER Neutral Format |
| 393 | NHP | N/A | NOAA Hydrophone Data |
| 394 | NKB | Native Instruments | Kontakt Audio Bank |
| 395 | NKM | Native Instruments | Kontakt Multi Instrument Format |
| 396 | NOPB | N/A | Navicat file |
| 397 | NOT | Notation Software | Notation Format |
| 398 | NOTX | Rick Meyers | E-Sword Study |
| 399 | NRE | Nero AG | Nero CD EXTRA Compilation |
| 400 | NSF | IBM | Lotus Notes Database |
| 401 | NTS | IBM | Lotus Notes Traveler Server Config Format |
| 402 | OAB | N/A | Offline Address Book |
| 403 | OBI | Microsoft | Outlook RSS Subscription Format |
| 404 | OBX | IBM | Rational XDE |
| 405 | OER | N/A | AU OER TOOLS project |
| 406 | OFFSETS | N/A | Offset |
| 407 | OFT | Microsoft | Outlook Format Template |
| 408 | OGEX | N/A | Open Game Engine Exchange data |
| 409 | OLB | Microsoft | OLE Object Library |
| 410 | OLK | Microsoft | Outlook Address Book Format |
| 411 | OLK14 | N/A | Microsoft Outlook for Mac message |
| 412 | OLK14CATEGORY | Microsoft | Outlook Category Format |
| 413 | OLK14CONTACT | Microsoft | Outlook Contact Format |
| 414 | OLK14EVENT | Microsoft | Outlook Calendar Event Format |
| 415 | OLK14EXMOVES | N/A | Microsoft Outlook 2011 for Mac data |
| 416 | OLK14EXSYNCMAP | N/A | Microsoft Outlook 2011 for Mac data |
| 417 | OLK14FOLDER | Microsoft Corporation | Microsoft Outlook 2011 For Mac Folder |
| 418 | OLK14IMAPSYNCMAP | N/A | Microsoft Outlook 2011 for Mac data |
| 419 | OLK14MESSAGE | Microsoft | Outlook Message Format |
| 420 | OLK14MSGSOURCE | Microsoft | Outlook Email Message Data Format |
| 421 | OLK14RECENT | Microsoft Corporation | Microsoft Outlook 2011 For Mac Recent Address |
| 422 | OLK14SCHEDULE | Microsoft Corporation | Microsoft Outlook 2011 For Mac Schedule |
| 423 | OLK14SEARCH | Microsoft Corporation | Microsoft Outlook 2011 For Mac Saved Search |
| 424 | OLK14SIGNATURE | Microsoft | Outlook Signature Format |
| 425 | OLK14UID | Microsoft Corporation | Microsoft Outlook 2011 For Mac UID |
| 426 | OLK15MESSAGE | N/A | Microsoft Outlook for Mac message |
| 427 | OLM | Microsoft | Mac Outlook Database Format |
| 428 | OLS | Microsoft Corporation | Microsoft Office List Shortcut |
| 429 | OMOD | N/A | Oblivion Mod Archive |
| 430 | ONE | Microsoft | OneNote Document |
| 431 | ONEPKG | Microsoft | Microsoft OneNote Package Format |
| 432 | ONEPKG_1033 | N/A | Microsoft update data |
| 433 | ONETOC | Microsoft Corporation | Microsoft OneNote Table Of Contents |
| 434 | ONETOC2 | Microsoft | Microsoft OneNote Table Of Contents Format |
| 435 | OOA | N/A | OOA Interchange Format Data |
| 436 | OPS | Microsoft | Office Profile Settings Format |
| 437 | OPT | Zeljko Finzgar | MySQL Database Data Format |
| 438 | OST | Microsoft | Outlook Offline Folder Format |
| 439 | OUT | N/A | Output Format |
| 440 | OVLX | N/A | Generic |
| 441 | OXF | N/A | IBM Rational Rhapsody |
| 442 | OYZ | dataBased Intelligence, Inc. | Lotus Approach Alternate DBASE Index |
| 443 | P3M | Adobe Systems | Adobe Photoshop Material Preset Format |
| 444 | PATCH | Matt Mackall | Patch |
| 445 | PCAP | Wireshark | Packet Capture Data |
| 446 | PCKGDEP | N/A | Microsoft Windows package deployment |
| 447 | PCQ | N/A | Pfaff Embroidery |
| 448 | PD | Corel Corporation | Corel Paradox Table Format |
| 449 | PD4 | Microsoft | Windows Live Photo Gallery Information Format |
| 450 | PDX | Adobe Systems | Adobe Acrobat Index Format |
| 451 | PED | Corel Corporation | Corel WordPerfect Program Editor Delete Save |
| 452 | PEK | Adobe Systems | Adobe Peak Waveform Format |
| 453 | PEQ | Corel Corporation | Corel WordPerfect Program Editor Print Queue |
| 454 | PER | Microsoft | Age Of Empires Personality Format |
| 455 | PFILE | Microsoft | Rights Management Protected File |
| 456 | PIL | CMA Microdialysis AB | CMA Microdialysis Trend Data |
| 457 | PIMA | Adobe Systems Incorporated | Adobe Application Manager Package |
| 458 | PKX | IBM | Rational XDE |
| 459 | PLB | Microsoft Corporation | FoxPro Library |
| 460 | PLG | Microsoft | Microsoft Developer Studio Build Log Format |
| 461 | PMA | Microsoft Corporation | Microsoft Windows Performance Monitor Data |
| 462 | PNACH | PCSX2 | PCSX2 Patch Format |
| 463 | PNDD | Symantec Corporation | Norton Disk Doctor |
| 464 | PNDE | N/A | Norton Utilities |
| 465 | POT | Microsoft | PowerPoint Template |
| 466 | POTM | Microsoft | PowerPoint Open XML Macro-Enabled Presentation Template |
| 467 | POTX | Microsoft | PowerPoint Open XML Presentation Template |
| 468 | PPA | Microsoft | PowerPoint Add-in |
| 469 | PPAM | Microsoft | PowerPoint 2007 Add-In |
| 470 | PPS | Microsoft | PowerPoint Slide Show |
| 471 | PPSM | Microsoft | PowerPoint Open XML Macro-Enabled Slide Show |
| 472 | PPSX | Microsoft | PowerPoint Open XML Slide Show |
| 473 | PPT | Microsoft | PowerPoint Presentation |
| 474 | PPTM | Microsoft | PowerPoint Open XML Macro-Enabled Presentation |
| 475 | PPTX | Microsoft | PowerPoint Open XML Presentation |
| 476 | PQF | Corel Corporation | Corel Presentations Runtime |
| 477 | PQW | Corel Corporation | Corel Presentations Runtime |
| 478 | PREXPORT | N/A | Premiere Export preset |
| 479 | PRI | Nokia | Qt Project Include Format |
| 480 | PRJ | Paragon Decision Technology | Project Format |
| 481 | PRLX | N/A | e-Sword 9.x prayer request data |
| 482 | PRMP | N/A | Generic |
| 483 | PROCPS | The GNOME Project | Gnome Desktop |
| 484 | PROCSPEC | N/A | SpectraSuite data |
| 485 | PRPRESET | N/A | Adobe Premiere Preset |
| 486 | PSF1 | N/A | PlayStation Sound Format |
| 487 | PSPPALETTE | N/A | Corel PaintShop Pro data |
| 488 | PST | Microsoft | Outlook Personal Information Store Format |
| 489 | PTZ | Thomson West | E-Transcript Bundle Format |
| 490 | PUZ | Microsoft | Microsoft Publisher Packed Format |
| 491 | PX | Corel Corporation | Corel Paradox Primary Database Index |
| 492 | Q | Cinematronics | Quantum Compressed File |
| 493 | QBE | Corel Corporation | Corel Quattro Pro Saved Query |
| 494 | QEF | Microsoft Corporation | Microsoft Excel Query |
| 495 | QFD | Intuit Inc. | Quicken Data |
| 496 | QHF | Ilgam Zulkorneev | QIP Saved History |
| 497 | QM | Nokia | Qt Compiled Translation Source Format |
| 498 | QRS | Corel Corporation | Corel WordPerfect Equation Editor Support |
| 499 | QUA | Avira Operations | Avira AntiVir Quarantined Format |
| 500 | RC1 | Samsung | Samsung Mobile Device Firmware Format |
| 501 | RDAT | N/A | RNA Data (RDAT) |
| 502 | RDD | ReliaSoft Corporation | ALTA |
| 503 | RDL | Corel Corporation | Corel Paradox Format |
| 504 | REAL | The GNOME Project | Gnome Desktop |
| 505 | REP | SAP AG | BusinessObjects Report Format |
| 506 | RF5 | Tektronix, Inc. | Tektronix |
| 507 | RFB | Siber Systems | RoboForm Bookmark Format |
| 508 | RFC | Siber Systems | RoboForm Contact Format |
| 509 | RFN | Siber Systems | RoboForm Safenote Format |
| 510 | RFO | Siber Systems | RoboForm Option Format |
| 511 | RFP | Siber Systems | RoboForm Passcard Format |
| 512 | RFQ | Siber Systems | RoboForm SearchCard Format |
| 513 | RFR | Adobe Systems Incorporated | Adobe Photoshop Frame Filter |
| 514 | RFX | Siber Systems, Inc. | RoboForm Blocked Passcard |
| 515 | RGE | Microsoft | Entourage Format Archive |
| 516 | RGRP | Avid Technology | Pro Tools Region Group Format |
| 517 | RLG | ReliaSoft Corporation | Weibull++ |
| 518 | ROP | N/A | Generic |
| 519 | RPMSG | Microsoft | Outlook Restricted Permission Message |
| 520 | RPT | SAP | Crystal Reports Format |
| 521 | RSC | Nokia | Resource Format |
| 522 | RSD | REAL | RealSQLDatabase Format |
| 523 | RSDS | N/A | SharePoint Shared Data Source |
| 524 | RSL | N/A | Robot Scripting Language |
| 525 | RTWSH | RapidSolution Software | Radiotracker Wishlist Format |
| 526 | RUS | GPS Moldova | Navitel Navigator Map |
| 527 | RVDATA | Enterbrain | RPG Maker VX Data Format |
| 528 | RXPROJ | Enterbrain, Inc. | RPG Maker Project |
| 529 | S01 | Corel Corporation | Corel WordPerfect Distribution Format |
| 530 | S02 | Corel Corporation | Corel WordPerfect Distribution Format |
| 531 | S03 | Corel Corporation | Corel WordPerfect Distribution |
| 532 | S4P | N/A | Touchstone 16 S-parameters Data |
| 533 | SAMBA3 | The GNOME Project | Gnome Desktop |
| 534 | SAS7BDAT | SAS Institute Inc. | SAS Database |
| 535 | SB2 | MIT | Scratch 2.0 Project File |
| 536 | SB3 | MIT | Scratch 3.0 Project File |
| 537 | SBL | Procedimientos-Uno, S.L. | Arquitienda Graphic Symbol Library |
| 538 | SBSTORE | Mozilla Corporation | Mozilla Firefox |
| 539 | SBT | URUWorks | SBT Subtitle Format |
| 540 | SBX | Adobe | Adobe Illustrator Tsume Format |
| 541 | SCBO | N/A | MacBook EFI unlock data |
| 542 | SCI | Scilab Enterprises | Virtumonde / Vundo Trojan Infected Format |
| 543 | SCVINFO | Microsoft Corporation | Windows Communication Foundation WCF Metadata |
| 544 | SDXF | N/A | Structured Data eXchange Format |
| 545 | SEARCH-MS | Microsoft | Windows Saved Search Format |
| 546 | SEARCHCONNECTOR-MS | Microsoft | Windows Search Connector Format |
| 547 | SECURITY | Oracle Corporation | Javasoft Jre 1.3 Lib Security |
| 548 | SEG1 | Smith Micro Software, Inc. | StuffIt Segment |
| 549 | SESSION | Dassault Systemes | CATIA 4 Session Format |
| 550 | SETUP | Crytek | CryENGINE Character Setup Format |
| 551 | SFA | Sony Corporation | Sony Sound Forge |
| 552 | SFV | N/A | Simple Format Verification Format |
| 553 | SGY | SEG Technical Standards Committee | SEG-Y Data File |
| 554 | SHA256 | FileVerifier++ | FileVerifier++ SHA-256 Hashes Format |
| 555 | SHLB | Mozilla Corporation | Mozilla |
| 556 | SHM | Corel Corporation | Corel WordPerfect Shell Macro Library |
| 557 | SHUTDOWNSTALL | Apple, Inc. | Mac OS X Log |
| 558 | SIDD | Apple | ITunes Authorization Data Format |
| 559 | SIDN | Apple, Inc. | Apple ITunes Authorization Data |
| 560 | SIG | N/A | Signature Format |
| 561 | SITES2 | Apple | IWeb Site Design Project |
| 562 | SKY | Microsoft Corporation | Microsoft Multiplan SYLK Spreadsheet |
| 563 | SLDM | Microsoft Corporation | Microsoft PowerPoint 2007/2010 Macro-enabled Open XML Slide |
| 564 | SLDX | Microsoft Corporation | Microsoft PowerPoint 2007/2010 Open XML Slide |
| 565 | SLIB | Synopsys, Inc. | Synopsys Interface Timing Specification Model |
| 566 | SLIP | Embarcadero Technologies, Inc. | CodeGear Licence |
| 567 | SLK | Microsoft | Symbolic Link Format |
| 568 | SLL | N/A | Static Link Library |
| 569 | SLMX | N/A | Simulink traceability data |
| 570 | SLR | Grassland, Soil & Water Research Laboratory | ArcSWAT Solar Radiation Input |
| 571 | SLTX | N/A | MATLAB Simulink model Template |
| 572 | SLXP | N/A | MATlab model |
| 573 | SM4 | RHK Technology, Inc. | RHK Technology Proprietary |
| 574 | SMB | Autodesk, Inc. | Autodesk Symbol Library |
| 575 | SMPO | N/A | Scalado SpeedView Meta Object |
| 576 | SMWT | Adobe Systems | Adobe InDesign Filter |
| 577 | SNAPFIRESHOW | Corel | Corel SnapfireShow Format |
| 578 | SNP | Microsoft | Access Report Snapshot |
| 579 | SOM | Corel Corporation | Corel Paradox Sort Information |
| 580 | SP1 | Microsoft Corporation | Microsoft Windows XP With Service Pack 1 Installation |
| 581 | SP2 | Super Ball 2 | Super Ball 2 Level Format |
| 582 | SP3 | Microsoft | Microsoft Windows XP With Service Pack 3 Installation Format |
| 583 | SPEF | N/A | Standard Parasitic Exchange Format |
| 584 | SPM | Corel Corporation | Corel WordPerfect |
| 585 | SPO | SPSS | SPSS Statistical Data Output Format |
| 586 | SPOTLIGHT-V100 | N/A | Apple Spotlight index |
| 587 | SQC | N/A | Generic |
| 588 | SQM | Microsoft | Service Quality Monitoring Format |
| 589 | SRG | Microsoft | Microsoft PowerPoint Self-registration Data Format |
| 590 | SRL | Procedimientos-Uno, S.L. | Arquitienda Local Database |
| 591 | SRX | N/A | SPARQL Query Results XML Format Result |
| 592 | SSC | Microsoft | SourceSafe Status Format |
| 593 | SSDF | N/A | Generic |
| 594 | SSMSASPROJ | N/A | Microsoft SQL Server Analysis Services Project |
| 595 | STAT | Richard Hughey - Kevin Karplus - Anders Krogh | Statistics |
| 596 | STATE | libretro | Windows Photo Gallery User |
| 597 | STUB | Apple, Inc. | Mac OS X Stub Library |
| 598 | SUN4 | Sun Microsystems, Inc. | SunOS Solaris 4 |
| 599 | SVCMAP | Microsoft Corporation | Windows Communication Foundation WCF Reference |
| 600 | SVD | Microsoft | Microsoft Word Document Autosave Format |
| 601 | SWB | Adobe Systems Incorporated | Adobe Photoshop |
| 602 | SWTAG | Adobe Systems Incorporated | Adobe Creative Suite Software Tag |
| 603 | SYNC | Apple, Inc. | Apple ColorSync |
| 604 | TALF | N/A | MAC OS X app licence |
| 605 | TBL | Blizzard Entertainment | Table Format |
| 606 | TBX | SDL plc. | Trados Glossary |
| 607 | TDS | Borland Software Corporation | Borland Turbo Debugger Symbol Table Format |
| 608 | TEMPLATE | Apple | Apple Pages Template |
| 609 | TER | Planetside Software | TerraGen Landscape |
| 610 | TERM | Apple, Inc. | Apple Mac OS X Terminal |
| 611 | TEXTEXPANDER | SmileOnMyMac, LLC | TextExpander |
| 612 | TEXTUTILS | The GNOME Project | Gnome Desktop |
| 613 | THMX | Microsoft | Office 2007 Theme Format |
| 614 | THS | Corel Corporation | Corel WordPerfect Thesaurus Dictionary |
| 615 | TIMESTAMP | ESRI | Geodatabase Timestamp File |
| 616 | TINY | The GNOME Project | Gnome Desktop |
| 617 | TIW | Bentley Systems, Incorporated | Bentley InRoads |
| 618 | TMPL | The Swish-e Project | SWISH-E Example Format |
| 619 | TNK | N/A | Generic |
| 620 | TOC | QUALCOMM | Eudora Table Of Contents |
| 621 | TOOL | Apple, Inc. | Apple Mac OS X Terminal |
| 622 | TOPX | Rick Meyers | E-sword Topic Note |
| 623 | TRASHES | Google Inc. | Google Android Mobile Phone |
| 624 | TRASHINFO | N/A | Trash Storage Metadata |
| 625 | TRAY | Corel | Corel CONNECT Tray Format |
| 626 | TRC | Oracle | Oracle Trace Format |
| 627 | TRIDEFLICENSE | N/A | Dynamic Digital Depth license |
| 628 | TRX | Microsoft | Visual Studio Test Results Format |
| 629 | TSC | Microsoft | Microsoft Windows WinHelp Related Format |
| 630 | TTBS | Microsoft Corporation | Microsoft PowerPoint For Mac Toolbar |
| 631 | TTY | Adobe Systems Incorporated | Macromedia Dreamweaver |
| 632 | TXT12 | N/A | IRI Scouting Database XML |
| 633 | UCCAPILOG | Microsoft | Microsoft UCC API Log Format |
| 634 | UDC | Adobe Systems | Adobe InDesign User Dictionary |
| 635 | UDT | N/A | Generic |
| 636 | UKR | N/A | Adobe Acrobat language resource data |
| 637 | UMF | GetMediaHolder | MediaHolder Universal Media Format |
| 638 | UMLX | Visual Object Modelers, Inc. | Visual UML XML Model |
| 639 | UPD | N/A | Program Update Information |
| 640 | UPJ | N/A | Ulead Project |
| 641 | UVR | N/A | UVR Mesh |
| 642 | UXDC | Microsoft Corporation | Microsoft Excel Data Retrieval Service Connection |
| 643 | V | Accellera | Verilog Source Code Format |
| 644 | V03 | Axialis Software | Axialis Thumbnail Cache |
| 645 | VAL | Corel Corporation | Corel Paradox Validity Check Format |
| 646 | VCE | Adobe | Adobe Audition (Cool Edit) NMS Format |
| 647 | VCS | N/A | VCalendar Event Format |
| 648 | VH | Microsoft Corporation | WinHelp VH |
| 649 | VIB | ChemSoft Ltd. | Chemsoft Export/Import MSDS Data |
| 650 | VIH | N/A | Video Metadata |
| 651 | VIR | Symantec | Virus-Infected Format |
| 652 | VNCLOC | Apple | Screen Sharing VNC Internet Location |
| 653 | VOL | N/A | Volume Format |
| 654 | VRGE08TASK | Microsoft Corporation | Microsoft Entourage 2008 Task |
| 655 | VRL | N/A | VRML Virtual World |
| 656 | VSD | Microsoft | Visio Drawing Format |
| 657 | VSDISCO | Microsoft | DISCO Dynamic Discovery Document |
| 658 | VSDX | Microsoft | Visio Drawing |
| 659 | VSO | NVIDIA Corporation | NVidia Compiled Vertex Shader |
| 660 | VSS | Microsoft | Visio Stencil Format |
| 661 | VST | Steinberg | VST Audio Plugin |
| 662 | VSX | Microsoft | Visio Stencil XML Format |
| 663 | VTC | ReliaSoft Corporation | ReliaSoft Related |
| 664 | VTI | Kitware, Inc. | Visualization Toolkit Image Data |
| 665 | VTV | Adobe Systems | Adobe Dreamweaver Validator Configuration Format |
| 666 | WBK | Microsoft | Word Document Backup |
| 667 | WCAP | N/A | Weston CAPture video |
| 668 | WCD | Microsoft | Works Calendar Format |
| 669 | WCH | Corel Corporation | Corel WordPerfect Macro Facility |
| 670 | WCINV-MS-P2P | Microsoft Corporation | Windows Meeting Space |
| 671 | WCP | Corel | WinDVD Creator Project Format |
| 672 | WEA | Autodesk | Ecotect Weather Format |
| 673 | WEEKLY | N/A | Week log |
| 674 | WER | Microsoft | Windows Error Report |
| 675 | WFLOW | Apple, Inc. | Apple Mac OS X Automator Workflow |
| 676 | WIX | Xara Group Limited. | Xara Internal Graphics Data |
| 677 | WLL | Microsoft | Microsoft Word Add-in |
| 678 | WMI | WorldMate Inc. | WorldMate Itinerary Data |
| 679 | WORK | Bibble Labs | Bibble Work Queue Format |
| 680 | WORKFLOW | Apple | Automator Workflow |
| 681 | WPC | Microsoft | WordPad Converter Format |
| 682 | WRAPPER | The GNOME Project | Gnome Desktop |
| 683 | WRTS | Wrts | Wrts File |
| 684 | WTL | Microsoft Corporation | Windows Test Log |
| 685 | WVP | Symantec | Symantec Virtual Package Editor Virtual Software Project Format |
| 686 | WZCLOUD | N/A | Generic |
| 687 | WZSUL | N/A | WinZip multi-user registration |
| 688 | X01 | Corel Corporation | Corel Paradox Secondary Index |
| 689 | X02 | Corel Corporation | Corel Paradox Secondary Index |
| 690 | X03 | Corel Corporation | Corel Paradox Secondary Index |
| 691 | X04 | Corel Corporation | Corel Paradox Secondary Index |
| 692 | X05 | Corel Corporation | Corel Paradox Secondary Index |
| 693 | X06 | Corel Corporation | Corel Paradox Secondary Index |
| 694 | X07 | Corel Corporation | Corel Paradox Secondary Index |
| 695 | X08 | Corel Corporation | Corel Paradox Secondary Index |
| 696 | X09 | Corel Corporation | Corel Paradox Secondary Index |
| 697 | XAB | Microsoft Corporation | Microsoft Outlook Express Address Book |
| 698 | XAR | MAGIX | Xara Xtreme Drawing |
| 699 | XBX | Microsoft Corporation | Xbox Icon Or Picture |
| 700 | XDXF | N/A | XML Dictionary eXchange Format |
| 701 | XEVGENXML | Adobe Systems Incorporated | Adobe Dreamweaver |
| 702 | XFO | N/A | XSL-FO Formatted Form |
| 703 | XG0 | Corel Corporation | Corel Paradox Secondary Index |
| 704 | XG1 | Corel Corporation | Corel Paradox Secondary Index |
| 705 | XG2 | Corel Corporation | Corel Paradox Secondary Index |
| 706 | XG3 | Corel Corporation | Corel Paradox Secondary Index |
| 707 | XG4 | Corel Corporation | Corel Paradox Secondary Index |
| 708 | XG5 | Corel Corporation | Corel Paradox Secondary Index |
| 709 | XHB | N/A | HomeBank Data |
| 710 | XIMG | N/A | Extended GEM bitmap |
| 711 | XL | Microsoft | Excel Spreadsheet |
| 712 | XLA | Microsoft | Excel Add-In Format |
| 713 | XLAM | Microsoft | Excel Open XML Macro-Enabled Add-In |
| 714 | XLB | Microsoft | Excel Toolbars Format |
| 715 | XLC | Microsoft | Excel Chart |
| 716 | XLD | Microsoft | Excel Database Format |
| 717 | XLKF | N/A | ABB license key |
| 718 | XLL | Microsoft | Excel Add-In Format |
| 719 | XLM | Microsoft | Excel Macro |
| 720 | XLS | Microsoft | Excel Spreadsheet |
| 721 | XLSB | Microsoft | Excel Binary Spreadsheet |
| 722 | XLSM | Microsoft | Excel Open XML Macro-Enabled Spreadsheet |
| 723 | XLSX | Microsoft | Microsoft Excel Open XML Spreadsheet |
| 724 | XLT | Microsoft | Excel Template |
| 725 | XLTM | Microsoft | Excel Open XML Macro-Enabled Spreadsheet Template |
| 726 | XLTX | Microsoft | Excel Open XML Spreadsheet Template |
| 727 | XLW | Microsoft | Excel Workspace Format |
| 728 | XMMAP | Mindjet | MindManager XML Map Format |
| 729 | XPT | N/A | Mozilla Firefox Component |
| 730 | XRDML | PANalytical B.V. | PANalytical XRD Measurement Data XML |
| 731 | XSF | Microsoft | InfoPath Form Definition Format |
| 732 | XSLB | N/A | Microsoft Excel data |
| 733 | XSN | Microsoft | InfoPath Form Template Format |
| 734 | XSSLOG | Microsoft Corporation | Microsoft SharePoint WorkSpace Groove Log |
| 735 | XSSR | Microsoft Corporation | Microsoft SharePoint WorkSpace Groove |
| 736 | XST | Microsoft | Microsoft Outlook Personal Folders Format |
| 737 | XSVF | Xilinx | Xilinx Serial Vector Format |
| 738 | Y01 | Corel Corporation | Corel Paradox Secondary Index |
| 739 | Y02 | Corel Corporation | Corel Paradox Secondary Index |
| 740 | Y03 | Corel Corporation | Corel Paradox Secondary Index |
| 741 | Y04 | Corel Corporation | Corel Paradox Secondary Index |
| 742 | Y05 | Corel Corporation | Corel Paradox Secondary Index |
| 743 | Y06 | Corel Corporation | Corel Paradox Secondary Index |
| 744 | Y07 | Corel Corporation | Corel Paradox Secondary Index |
| 745 | Y08 | Corel Corporation | Corel Paradox Secondary Index |
| 746 | Y09 | Corel Corporation | Corel Paradox Secondary Index |
| 747 | YCT | David Binette | YahELite Chat Transcript |
| 748 | YG0 | Corel Corporation | Corel Paradox Secondary Index |
| 749 | YG1 | Corel Corporation | Corel Paradox Secondary Index |
| 750 | YG2 | Corel Corporation | Corel Paradox Secondary Index |
| 751 | YG3 | Corel Corporation | Corel Paradox Secondary Index |
| 752 | YG4 | Corel Corporation | Corel Paradox Secondary Index |
| 753 | YWL | Repkasoft | YoWindow Data |
| 754 | _GS | Siber Systems, Inc. | Roboform GoodSync Data |
| 755 | _P | N/A | Generic |
| 756 | _VBXSLN90 | N/A | Microsoft Visual Studio data |
