There is only one file type that uses the .LUC extension:
Compiled Lua Source File
Compiled Source code file used to extend applications such as PC video games; contains a compiled .LUA script.
LUA is a light-weight programming language designed to extend applications. LUA files may be used to customize certain applications, such as the World of Warcraft and Dawn of War video games. However, World of Warcraft does not read compiled LUA scripts (LUC files).
NOTE: LUC files are produced using the luac.exe, which is part of the LuaBinaries package. Most LUC files can be decompiled with LuaDec.
Updated: April 18, 2015