WinAce is an archiving program for Windows with its own "ACE" compressed archive format and built-in support for other common archive formats types such as ZIP, RAR and CAB. They also offer a freeware (but not free software) command-line decompression (including listing and testing) program called Unace for Mac OS X and Linux.
WinAce peaked in popularity around 2000, but since fallen in popularity to WinRAR and Windows' built-in Zip functionality.