.XUI File Extension
File TypeXbox 360 User Interface File
What is a XUI file?
Skin file used by "modded" Xbox 360 game consoles; created and edited by the Xbox UI Tool, which is part of Microsoft's Xbox SDK; saves graphics and layout information for the dashboard; used for customizing the look and feel of the Xbox interface.
XUI files are actually compiled into binary .XUR files, which are the UI files used by the Xbox.