slackbuilds_ponce/system/nomarch

nomarch lists/extracts/tests '.arc' archives. (It also handles '.ark'
files). This is a *very* outdated file format which should never be
used for anything new, but unfortunately, you can still run into it
every so often (especially if you mess about with old CP/M stuff). So
nomarch is a handy as a way to deal with these files.