| wsx | WinMX Server Information File |
| wsxz | SDL WorldServer WSXZ Package |
| wsz | WinAMP Skin |
| wt | WiredTiger Database Dump |
| wt4 | Win-Test Binary Log |
| wta | Tennis Navigator WTA Data File |
| wtb | Win-Test Binary Log |
| wtc | Wikitude Studio Image Collection Data |
| wtf | WinTaper Data File |
| wtf | WaveThunder Factory Data |
| wtfav | Watchtower Library Favourites Data |
| wtg | WAsP Wind Turbine Generator Data |
| wth | CONTAM Weather Data |
| wtk | WinTalk URL |
| wtl | Windows Test Technologies Logger Results |
| wtm | WaveThunder Music Data |
| wtml | WorldWide Telescope Collection Data |
| wto | Wikitude Studio Object |
| wtpl | WireTap Studio Library |
| wtr | FARSITE Weather Data |
| wtr | SimSig WTT Timetable Rules |
| wts | WebPlus Theme Set |
| wtt | SimSig WTT Timetable |
| wtw | WaveThunder WAV Shadow Data |
| wtx | WinTune Report |
| wty | WaveThunder Player Data |
| wu | Watchfire Bobby URL List |
| wud | Cast Soft wysiwyg User Data |
| wui | WhatsUp Gold Network Map Polling Statistics Data |
| wul | WinUHA Language Data |
| wup | WhatsUp Gold Network Map |
| wusikefx | Wusikstation Effect Data |
| wusikfxprst | Wusikstation FX Preset Data |
| wusiklib | Wusikstation Library Data |
| wut | WUTG Tag Data |