That would be my guess, Charles Mingus is arguably the best bassist ever. He can take just about anything, whether it is gospel, jazz or whatever, and weave it into a masterpiece that delights the senses.
Well, Matt is himself a Jazz musician, and enjoys everything Jazz.
Naming finale WP releases after Jazz legends is, as I understand, sort of a habit 🙂 Bird was considered for 1.2, but Mingus was chosen. http://photomatt.net/jazzquotes/