OpenRC is the dependency-based init system used by NetBSD, Alpine Linux, Gentoo, and other select operating systems. TrueOS is using OpenRC for managing system services rather than FreeBSD's RC.
TrueOS developers are fond of the design, the system service manager is simpler, and boot times have been reduced from about one minute to around ten seconds.
Those wishing to learn more about TrueOS' use of OpenRC can read this blog post. with all of the details.