Error in docs? (Installing syslog server functionality)

For using syslog-ng it says in the docs (Syslog - LibreNMS Docs):

source s_net {
        tcp(port(514) flags(syslog-protocol));
        udp(port(514) flags(syslog-protocol));
};

destination d_librenms {
        program("/opt/librenms/syslog.php" template ("$HOST||$FACILITY||$PRIORITY||$LEVEL||$TAG||$R_YEAR-$R_MONTH-$R_DAY $R_HOUR:$R_MIN:$R_SEC||$MSG||$PROGRAM\n") template-escape(yes));
};

log {
        source(s_net);
        source(s_src);
        destination(d_librenms);
};

IMHO the entry “source(s_src)” points to nowhere, as this directive is not defined before. So, is it orphaned and can simply be ommitted, or what is the missing line for “s_src” definition?

Could it be that the following lines are just missing in the docs?

source s_src {
   system();
   internal();
};

From my understanding, this would also catch local syslogs, which makes sense.

Can anyone please confirm this? Or if that’s not true, what’s the correct syntax of that file?