lrzip is a file compression utility and compressed file format. It was adapted from rzip, but is not compatible with it. Like rzip, it bases its high compression rate on the exploitation of long-range redundancies in the data set being compressed.
Lrzip compression seems to consist of two steps: the long-range redundancy elimination, and then the use of a more conventional compression algorithm. Lrzip gives (as of 2019) options to use Bzip2, Gzip, LZO, and ZPAQ compression for the latter step (as well as no compression). However, the result of this will not be a Bzip2, Gzip, etc. file with the Lrzip bytestream inside of it, but rather, another Lrzip file, which only uses these compression formats internally. Thus, the format indicated by an extension like ".lrz.gz" is somewhat ambiguous; it could mean that the file is a Gzip file containing an Lrzip-compressed file, or it could mean that the file is an Lrzip file that uses Gzip internally. The first makes a lot more sense, but this not being true has not stopped anybody in the past.
The author suggests that lrzip could stand for either Long Range ZIP or Lzma RZIP.
Files begin with ASCII signature "