Mailaender [1] filed a deletion request for mmass [2]: This package is broken because upstream deleted its website. Also, the README states that this was tested with dependencies from 2013 and it is known not to work with more recent versions of wxPython and Numpy so it is impossible to maintain here. I created a Flatpak instead, which bundles the old dependencies.
[1] https://aur.archlinux.org/account/Mailaender/ [2] https://aur.archlinux.org/pkgbase/mmass/
