gzip package:zlib

Compression and decompression of data streams in the gzip format. The format is described in detail in RFC #1952: http://www.ietf.org/rfc/rfc1952.txt See also the zlib home page: http://zlib.net/

The gzip format uses a header with a checksum and some optional meta-data about the compressed file. It is intended primarily for compressing individual files but is also sometimes used for network protocols such as HTTP. The format is described in detail in RFC #1952 http://www.ietf.org/rfc/rfc1952.txt

This is not a format as such. It enabled zlib or gzip decoding with automatic header detection. This only makes sense for decompression.