It fixes many bugs present in current versions in the tree
Can you try this ebuild? https://gitlab.com/KenjiBrown/gentoo-overlay/-/blob/KBrown-pub/net-mail/dbmail/dbmail-3.3.1.ebuild
I have trued the ebuild from https://gitlab.com/KenjiBrown/gentoo-overlay/-/blob/KBrown-pub/net-mail/dbmail/dbmail-3.3.1.ebuild (by copying it into a local overlay). For me it doesn't work, the install phase fails. After adding mkdir -p "${D}/usr/lib/tmpfiles.d" mkdir -p "${D}$(systemd_get_systemunitdir)" at the top of src_install(), it does work for me. It seems that the command emake DESTDIR="${D}" SYSTEMD_UNIT_DIR="$(systemd_get_systemunitdir)" install assumes these directories already exist.