Head-to-head comparison of Phar, Tar and Zip
Zip-based phars
What makes a phar a phar and not a tar or a zip?
PHP Manual

## Tar-based phars

Archives based on the tar file format follow the more modern USTAR file format. The design of the tar file header makes them more efficient to access than the zip file format, and almost as efficient as the phar file format. File names are limited to 255 bytes, including full path within the phar archive. There is no limit on the number of files within a tar-based phar archive. These archives can fully compressed in gzip or bzip2 format and still be executed by the Phar extension.

To compress an entire archive, use Phar::compress. To decompress an entire archive, use Phar::decompress.