Generally, the general Linux compressed packages finish in tar.gz
Tar is used for packaging files together, e.g. for distribution via the Internet.
The resulting archive, a "tar file" (humourously, "tarball") is often compressed, using ?gzip or some other form of compression
Gzip reduces the size of the named files using Lempel-Ziv ?LZ77 compression. Whenever possible, each file is replaced by one with the filename extension ".gz". Compressed files can be restored to their original form using gzip -d or gunzip or zcat.