Currently the network autodiscovery key is missing from the freebsd agent. Currently I have to work around with the following

UserParameter=net.if.discovery,ifconfig | awk ' BEGIN { print "

{\"data\":\[" }

/^[a-z0-9]+\:/ { gsub(/\:/,"",$ 1); if ( $ 1 != "lo0" ) print "{ \"

{#IFNAME}\":\"" $ 1"\" }," } END { print "{ \"{#IFNAME}

\":\"lo0\"} \n]}" } '

This works fine but should really be fixed properly with system calls and merged into the code stack. I can help with testing here if needed.