Missing rcvar field on FreeBSD

When running on FreeBSD, the generated file (/usr/local/etc/rc.d/servicename) does not contain a line for "rcvar". As far as I can tell from the FreeBSD manual at https://man.freebsd.org/cgi/man.cgi?rc.subr(8)

This makes it not possible to automatically start the service on boot. Usually, the value of the variable could be the name of the service in lowercase letters followed by _enable. For example in AdGuard Home:

name="AdGuardHome"
rcvar="adguardhome_enable"