There is only one file type that uses the .UNITY extension:
Unity Scene File
File created by Unity, a 3D engine primarily used to create video games; contains a unique level within a 3D game that includes objects, environments, decorations, cameras, lighting, and obstacles; used with other scenes to build a virtual world when editing.
Unity can be used to build 3D games for the Web, Nintendo Wii, iPhone, or as standalone applications for Windows and Mac OS X.
|Unity Technologies Unity||Commercial|
Updated: March 8, 2010