MarsSeed [1] filed a deletion request for knyttunderground [2]: Upstream website and domain name does not exist. It seems this game is not available for purchase and download from its creator.
However, it is offered on Steam. This package is not needed and not properly compatible with that distribution. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/knyttunderground/
