| wtr | SimSig WTT Timetable Rules |
| wts | WAsP Wind Turbine Site |
| WebPlus Theme Set |
| wtt | Likno Web Tooltips Builder Data |
| SimSig WTT Timetable |
| wtw | WaveThunder WAV Shadow Data |
| wtx | 3DCS Model Data |
| WinTune Report |
| wtxt | WildTangent Text Data |
| wty | WaveThunder Player Data |
| wu | Watchfire Bobby URL List |
| wud | Cast Soft wysiwyg User Data |
| wug | Twister Flasher Flash Data |
| wui | WhatsUp Gold Network Map Polling Statistics Data |
| wul | WinUHA Language Data |
| wup | WhatsUp Gold Network Map |
| wus | SWAT Water Use Input Data |
| wusikefx | Wusikstation Effect Data |
| wusikfxprst | Wusikstation FX Preset Data |
| wusiklib | Wusikstation Library Data |
| wut | WUTG Tag Data |
| wvc | WavPack Correction Data |
| wvd | StarMoney Filter Data |
| wve | DivX Conversion Data |
| wvf | Yokogawa Waveform Data |
| wvi | Anritsu IQ Producer Waveform Data |
| wvm | Ricardo WAVE Input |
| wvoc | wordPROF French Vocabulary Data |
| wvs | Wanvas Data |
| wvt | ANSYS AQWA Wind Velocity Data |
| IDGS101 Waveform Data |
| ww4 | WinWhatWhere Activity Log |
| ww6 | Nolo Willmaker 6 Will Data |
| wwa | WebSite-Watcher Archive |
| wwb | Corel WordPerfect Button Bar Data |
| wwcx | Adobe InCopy WWCX Data |
| wwd | Microsoft Works Wizard Data |
| Warrior Well Diagram |
| wwf | WAsP Wind Farm Data |
| wwg | CARE-S InfoWorks Wastewater Data |
| wwh | WAsP Workspace |
| wwi | WinWein Interchange Format Data |
| wwk | Corel WordPerfect Keyboard Layout Data |
| WAsP v7 Workspace |
| wwls | Weather Watcher Live Skin |
| wwm | WeeWheel Macro |
| wwp | Microsoft Works Wizard Data |
| wwq | SWAT Watershed Water Quality Input |
| wwr | WAsP v8 Resource Grid |
| wws | Microsoft Autoroute User Data |
| wwtfig | WorldWide Telescope Constellation Figures Data |
| wwtl | WorldWide Telescope Layer Data |
| wwu | Wwise Work Unit |
| wwx | winIDEA Watch XML Format Data |
| wxp | Redatam ASCII Dictionary Data |
| wxWidgets Package Description Data |
| wxs | WeChat Script |
| wxss | WeChat StyleSheets Data |
| wxw | Winradio Extended Wave Data |
| wxx | Worldographer Map Settings Data |
| wyc | wyBuild Version Data |
| wyUpdate Compressed Client Data |
| wys | Cast Soft wysiwyg v2 Data |
| wyBuild Server Data |
| wyu | wyBuild Update Data |
| wzcloud | WinZip Cloud Data |
| wzct | AbleCommerce Wizard Configuration Backup |
| wzd | Sharp Wizard Data |
| wzf | AbleCommerce Wizard Form Data |
| wzi | AbleCommerce Wizard Index Data |
| wzmul | WinZip Registration Data |
| wzo | AbleCommerce Wizard Output Data |
| wzsul | WinZip Multi-user Registration Data |
| wztheme | WinZip Theme Data |
| x | XView Object |
| x00 | Paradox Secondary Index |
| XTreeGold for Dos Help Data |
| x01 | Paradox Secondary Index |
| x02 | Paradox Secondary Index |
| x03 | Paradox Secondary Index |
