| .BIN | Unknown Developer | Ficheiros de Imagem de Disco | Binary Disk Image File | Unreal Tournament | Epic Games |
| .CWG | Epic Games | Ficheiros de Jogo | Castle Of The Winds Data | Castle of the Winds | Epic Games |
| .DAT | Unknown Developer | Ficheiros de Jogo | Game Data | Unreal Tournament | Epic Games |
| .DDT | Sports Interactive | Ficheiros de Jogo | Football Manager Keep Player Data File | Jill Of The Jungle | Epic Games |
| .DEM | Valve | Ficheiros de Jogo | Video Game Demo File | Unreal Tournament | Epic Games |
| .DZ | Digital Extremes | Ficheiros de Jogo | Land Of The Dead Level File | Unreal Tournament | Epic Games |
| .ESN | Epic Games | Ficheiros de Jogo | Unreal Engine Language Localization | Unreal Tournament | Epic Games |
| .FRA | Electronic Arts | Ficheiros de Jogo | FIFA World Cup Game Data | Unreal Tournament | Epic Games |
| .J2A | Epic Games | Ficheiros de Imagem 3D | Jazz Jackrabbit 2 Animation Data | Jazz Jackrabbit 2 | Epic Games |
| .J2B | Epic Games | Ficheiros de Jogo | Jazz Jackrabbit 2 Music Data | Jazz Jackrabbit 2 | Epic Games |
| .J2D | Epic Games | Ficheiros de Jogo | Jazz Jackrabbit Data File | Jazz Jackrabbit | Epic Games |
| .J2E | Epic Games | Ficheiros de Jogo | Jazz Jackrabbit 2 Episode File | Jazz Jackrabbit 2 | Epic Games |
| .J2H | Epic Games | Ficheiros de Jogo | Jazz Jackrabbit 2 High Scores | Jazz Jackrabbit 2 | Epic Games |
| .J2I | Epic Games | Ficheiros de Jogo | Jazz Jackrabbit 2 Internet Server Link File | Jazz Jackrabbit 2 | Epic Games |
| .J2L | Epic Games | Ficheiros de Jogo | Jazz Jackrabbit 2 Level File | Jazz Jackrabbit 2 | Epic Games |
| .J2S | Epic Games | Ficheiros de Imagem 3D | Jazz Jackrabbit 2 Language Data | Jazz Jackrabbit 2 | Epic Games |
| .J2T | Epic Games | Ficheiros de Jogo | Jazz Jackrabbit 2 Tile Set | Jazz Jackrabbit 2 | Epic Games |
| .J2V | Epic Games | Ficheiros de Vídeo | Jazz Jackrabbit 2 Cinematic File | Jazz Jackrabbit 2 | Epic Games |
| .JN1 | Epic Games | Ficheiros de Jogo | Jill Of The Jungle Data File | Jill Of The Jungle | Epic Games |
| .JPN | Microsoft Corporation | Ficheiros de Sistema | Windows Japanese Noise-Word List File | Unreal Tournament | Epic Games |
| .KA | Epic Games | Ficheiros de Jogo | Karma Engine Asset Data | Unreal Tournament | Epic Games |
| .KOR | Epic Games | Ficheiros de Jogo | Unreal Engine Language Localization | Unreal Tournament | Epic Games |
| .PSA | Epic Games | Ficheiros de Imagem 3D | Unreal Engine Skeletal Animation File | Unreal Tournament | Epic Games |
| .PSK | Epic Games | Ficheiros de Imagem 3D | Unreal Engine Skeletal Mesh File | Epic Games Unreal Engine | Epic Games |
| .T3D | Epic Games | Ficheiros de Imagem 3D | Unreal Engine 3D Object File | Unreal Tournament | Epic Games |
| .U | Epic Games | Ficheiros de Jogo | Unreal Tournament Class Package | Unreal Tournament | Epic Games |
| .UAX | Epic Games | Ficheiros de Áudio | Unreal Audio Package | Unreal Tournament | Epic Games |
| .UC | Epic Games | Ficheiros de Jogo | UnrealScript Class | UnrealEd | Epic Games |
| .UHTM | Epic Games | Ficheiros de Jogo | Unreal Tournament Data File | Unreal Tournament | Epic Games |
| .UKX | Epic Games | Ficheiros de Jogo | Unreal Animation Package | Unreal Tournament | Epic Games |
| .UMAP | Epic Games | Ficheiros de Jogo | Unreal Engine Map File | Unreal Tournament | Epic Games |
| .UMOD | Epic Games | Ficheiros de Jogo | Unreal Tournament Module File | Unreal Tournament | Epic Games |
| .UMX | Epic Games | Ficheiros de Jogo | Unreal Music Package | Unreal Tournament | Epic Games |
| .UNR | Unreal Software | Ficheiros de Jogo | Unreal Level Map | UnrealEd | Epic Games |
| .UPK | Epic Games | Ficheiros de Jogo | Unreal Engine 3 Package | Unreal Tournament | Epic Games |
| .USA | Microsoft Corporation | Ficheiros de Dados | American English Localization Language File | Unreal | Epic Games |
| .USX | Epic Games | Ficheiros de Jogo | Unreal Static Meshes | UnrealEd | Epic Games |
| .UT2 | Epic Games | Ficheiros de Jogo | Unreal Tournament 2003/2004 Map | Unreal Tournament | Epic Games |
| .UT2MOD | Epic Games | Ficheiros de Jogo | Unreal Tournament 2003/2004 Module File | Unreal Tournament 2003 | Epic Games |
| .UT3 | Epic Games | Ficheiros de Jogo | Unreal Tournament 3 Map File | Unreal Tournament | Epic Games |
| .UT4MOD | Epic Games | Ficheiros de Jogo | Unreal Tournament 2004 MOD Installation Package File | Unreal Tournament 2004 | Epic Games |
| .UTX | Epic Games | Ficheiros de Jogo | Unreal Texture Package | Unreal Tournament | Epic Games |
| .UVX | Epic Games | Ficheiros de Jogo | Unreal Tournament 2003 Saved Game File | Unreal Tournament 2003 | Epic Games |
| .UXX | Epic Games | Ficheiros de Jogo | Unreal Tournament 2003 Cache File | Unreal Tournament 2003 | Epic Games |
| .UZ | Epic Games | Ficheiros de Dados | Unreal Tournament Server File | Unreal Tournament | Epic Games |
| .VERSION | Open Source | Ficheiros de Dados | Linux GateD Daemon Data | Unreal Tournament | Epic Games |
| .XXX | BloodDolly | Ficheiros Encriptados | TeslaCrypt 3.0 Ransomware Encrypted File | Unreal Tournament | Epic Games |
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