Some things are distributed in compressed ".lz" files; for example, look at http://ftp.gnu.org/gnu/ddrescue/ : http://ftp.gnu.org/gnu/ddrescue/ddrescue-1.9.tar.lz . .lz are treated by lzip. http://en.wikipedia.org/wiki/Lzip : lzip is a program that implementats the LZMA compression algorithm. The project came about due to dissatisfaction with lzma-utils (another LZMA compressor), which produces files without an identification string (magic bytes) and without a checksum[1].
lzip-1.8-alt1 -> sisyphus: * Sun Sep 20 2009 Michael Shigorin <mike@altlinux> 1.8-alt1 - initial build for ALT Linux Sisyphus (spec from PLD) (closes: #18124)