There is only one file type that uses the .UC2 extension:
UltraCompressor 2 Archive
A UC2 file is a compressed archive created using UltraCompressor II, a legacy compression program. It contains one or more compressed files. UC2 compression supports OS/2 extended attributes and Windows 95 long filenames.
UltraCompressor II and UltraExpander II were DOS and Windows compression and decompression programs released in 1994. Users could use UltraCompressor II to compress and store files in UC2 archives, in the interest of saving hard drive space or more easily sharing files with others. They could then use UltraExpander II to extract files from UC2 archives.
Notably, UltraCompressor II analyzed files' content before compressing them, allowing it to compress files more compactly than some of the era's other compression programs. However, this extra analysis increased UltraCompressor II's compression times.
In Windows, you can attempt to install UltraExpander II in a DOS emulator, such as DOSBox, and use it to decompress your UC2 archive.
In Linux, you can use the free program unuc2 to decompress your UC2 archive.
Updated: February 17, 2021