diff --git a/share/man/man5/rc.conf.5 b/share/man/man5/rc.conf.5
--- a/share/man/man5/rc.conf.5
+++ b/share/man/man5/rc.conf.5
@@ -4956,6 +4956,16 @@
 .Dq Li YES ,
 these are the flags to pass to the
 .Xr sendmail 8
+.It Va precious_machine
+If set to
+.Dq Li YES ,
+some destructive actions require removal of the action-specific safe-belts
+before being allowed.
+For instance, the file
+.Pa /var/run/noshutdown
+is created to prevent
+.Xr shutdown 8
+targeted at the wrong machine.
 .El
 .Sh SERVICE JAILS
 The service jails part of the rc system automatically puts a service