Convert xpi to bzip2

What is the difference between .xpi and .bzip2?

Description: Efficient XML Interchange (EXI) is a binary XML format for exchange of data on a computer network. It was developed by the W3C's Efficient Extensible Interchange Working Group and is one of the most prominent efforts to encode XML documents in a binary data format, rather than plain text. Using EXI format reduces the verbosity of XML documents as well as the cost of parsing. Improvements in the performance of writing (generating) content depends on the speed of the medium being written to, the methods and quality of actual implementations.; It is an open-source file compressor and decompressor that is freely available and uses the Burrows-Wheeler codec. It isn't a file archiver as it compresses single files.