You can either get the version from https://moodle.org/plugins/ and install it over the web, or you can fetch it by using
cd /var/www/html/
git clone https://github.com/ndunand/moodle-qtype_matrix.git ./question/type/matrix
and continue installing from the web.
Question type written by Penny Leach at Liip [email protected]
[email protected] copyright 2011 University of Geneva