Propellor is in the early stages of supporting FreeBSD. It should basically work, and there are some modules with FreeBSD-specific properties.
However, many other properties only work on a Debian Linux system, and need
additional porting to support FreeBSD. Such properties have types like
Property DebianLike. The type checker will detect and reject attempts
to combine such properties with Property FreeBSD.
Sample config file which configures a FreeBSD system, as well as a Linux one.