Like the Frivolity package that it accompanies, it is written in Jason McIntosh (after an initial nudge by Andy Turner).
You can find the final Friv release as part of http://prdownloads.sourceforge.net/volity/Frivolity-0.5.2.tar.gz?download
As of version 0.6.0, Friv is no longer packaged with Frivolity.
Friv contains embedded documentation in Perl's POD format; you can use the perldoc
command to read it, or man
after it's been installed. You can also [view the docs as HTML].