Major contributions:

Chris Jones <chris.e.jones@gmail.com> -- original author
Francesco Fumanti <francesco.fumanti@gmx.net>
Gerd Kohlberger <gerdko gmail com>
marmuta <marmvta@googlemail.com> -- major developer since a few years


Small contributions:

Alan Bell <alanbell@ubuntu.com>
Barry Warsaw <barry@ubuntu.com>
Henrik Nilsen Omma <henrik@ubuntu.com>
Jeremy Bicha <jbicha@ubuntu.com>
Johannes Almer
Luke Yelavitch <luke.yelavich@canonical.com>
Martin Böhm <martin.bohm@kubuntu.org>
Martin Wimpress <martin@flexion.org>
Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
Simon Schumann <simon.schumann@web.de>
Ubuntu Core Developers <ubuntu-devel-discuss@lists.ubuntu.com>