I believe the original Almquist shell is used on FreeBSD. I know on Debian dash is the sh implementation (afterall it is Debian Almquist Shell), but the default login shell for the root user is bash apparently.

You may know Zsh as the default shell for FreeBSD

I thought on FreeBSD tcsh was default for root and sh was default for other users. Also never realized anyone used dash as a login shell :b