| .trim.cia |
Trimmed CTR Importable Archive |
| .unity |
Unity Scene File |
| .unity3d |
Unity Web Player File |
| .upk |
Unreal Engine 3 Package |
| .udk |
Unreal Engine Map File |
| .unf |
UNIF ROM File |
| .usx |
Unreal Static Meshes |
| .ut2 |
Unreal Tournament Map |
| .utx |
Unreal Texture Package |
| .umx |
Unreal Music Package |
| .unr |
Unreal Level Map |
| .uxx |
Unreal Tournament Cache |
| .u |
Unreal Tournament Class Package |
| .uc |
UnrealScript Class |
| .utxt |
Unicode Text File |
| .utc |
Bioware Creature File |
| .usa |
Unreal Saved Game File |
| .umod |
Unreal Tournament Module File |
| .ut2mod |
Unreal Tournament 2003/2004 Module File |
| .ut3 |
Unreal Tournament 3 Map File |
| .ukx |
Unreal Animation Package |
| .uvx |
Unreal Tournament 2003 Saved Game |
| .ut4mod |
Unreal Tournament 2004 Module |
| .uop |
Uniform Office Presentation |