There is only one file type that uses the .WCAT extension:
WinCatalog Collection File
File created by WinCatalog, a program used to index file information in Windows; contains an index of information about discs, hard drive files, and folders; helps users perform fast searches in place of the Windows search.
WCAT files include information about the contents of compressed files, multimedia files, and audio CDs. For example, WinCatalog extracts ID3 information from .MP3 files as well as EXIF information from digital photographs.
Updated: May 30, 2011