Adelie (musl-posix) must be getting really close to replacing sysv/openrc with full s6.
sysv is done: on Adélie, you can now choose between sysvinit and s6-linux-init as your init system. Both are supported. Providing a packaged alternative to OpenRC, however, will be much more difficult and time-consuming. It will have to wait until I can free a year, which should be slowly approaching. -- Laurent