ribugent [1] filed a deletion request for mailspring-bin [2]: Duplicated of https://aur.archlinux.org/packages/mailspring and doesn't follow the guidelines, it should be like mailspring-electron because it requires to use system electron package.
[1] https://aur.archlinux.org/account/ribugent/ [2] https://aur.archlinux.org/pkgbase/mailspring-bin/
