Trying to following instructions and options in rc.conf(5) on how to configure and utilise the automount facility, I found - nothing! Nothing on autofs, automount, automountd and autounmountd so far, as the keywords are already in etc/defaults/rc.conf. It is also confusing having "autofs" and "automount" - one wants to restart the automount facility has to issue service automount restart to ensure both the daemons of automountd and autounmountd have restarted in order - based upon "autofs_enable" I would consider service autofs restart which isn't.
https://reviews.freebsd.org/D3671
A commit references this bug: Author: trasz Date: Fri Oct 9 08:13:59 UTC 2015 New revision: 289060 URL: https://svnweb.freebsd.org/changeset/base/289060 Log: Document iSCSI and autofs(5) variables in rc.conf(5). PR: 203119 Reviewed by: bjk@ MFC after: 1 month Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D3671 Changes: head/share/man/man5/rc.conf.5
I've documented it in r289060. Note that as for restarting, you only need to restart automountd(8) or autounmountd(8) if you change the flags - otherwise the only thing you need to do is to reload mounts using automount(8), ie do "service automount restart".
MFC-ed to 10 in r293694.