Package lrzsz: Information

Lrzsz (consisting of lrz and lsz) is a cosmetically modified
zmodem/ymodem/xmodem package built from the public-domain version of the
rzsz package.  Lrzsz was created to provide a working GNU copylefted
Zmodem solution for Linux systems.

Under certain circumstances, Zmodem is the main protocol that is used to
transfer files.

You should install lrzsz if you're also installing a Zmodem communications
program that uses it. Minicom is an example of such a program.