Bzip UNIX Compressed File (.BZ, replaced by .BZ2)

An open source, freely available compression program. The PPM family of statistical compressors typically produces the maximum compression for a file and Bzip compresses 85-90% of that goal. It accomplishes this by being twice as fast
on compression and some six times faster on decompression.

WinRAR provides basic operations for .bz2 files created by other tools: view contents, extract files, show comments and archive information.

You can use the convert function to convert .bz2 files into .rar format.

You do not need to have any external programs to handle these formats.