sys-auth/seatd does not install a systemd service file while providing an openrc init file. This can easily be remedied by installing the service file in the 0.4.0 tarball at path 'contrib/systemd/seatd.service'. It appears to be equivalent to the provided init file.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=dc8edaa92db78c8d861d15f2ee252ed1eb88141f commit dc8edaa92db78c8d861d15f2ee252ed1eb88141f Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me> AuthorDate: 2020-12-07 17:37:27 +0000 Commit: Joonas Niilola <juippis@gentoo.org> CommitDate: 2020-12-11 07:58:09 +0000 sys-auth/seatd: Install systemd service file Closes: https://bugs.gentoo.org/754657 Signed-off-by: Haelwenn (lanodan) Monnier <contact@hacktivis.me> Closes: https://github.com/gentoo/gentoo/pull/18555 Signed-off-by: Joonas Niilola <juippis@gentoo.org> sys-auth/seatd/{seatd-0.4.0.ebuild => seatd-0.4.0-r1.ebuild} | 4 ++-- sys-auth/seatd/seatd-9999.ebuild | 3 ++- 2 files changed, 4 insertions(+), 3 deletions(-)