It was forked from unarr, which originated as a port of the RAR
extraction features from The Unarchiver project required for
extracting images from comic book archives. Zeniko wrote unarr as an
alternative to libarchive which didn't have support for parsing
filters or solid compression at the time.

While (lib)unarr was started with the intent of providing unarr with a
proper cmake based build system suitable for packaging and
cross-platform development, it's focus has now been extended to
provide code maintenance and to continue the development of unarr,
which no longer is maintained.

WWW: https://github.com/selmf/unarr