/etc/netstart in head still references /etc/rc.d/mroute6d deleted in r298512. Solution: remove line 55 in /etc/netstart.
Over to committer of 298512.
Thanks for reporting
A commit references this bug: Author: bapt Date: Sat Jun 25 12:54:28 UTC 2016 New revision: 302198 URL: https://svnweb.freebsd.org/changeset/base/302198 Log: Remove reference to mroute6d in /etc/netstart. mroute6d has been removed in r298512. PR: 209405 Submitted by: Trond.Endrestol@ximalas.info Approved by: re (gjb) Changes: head/etc/netstart