If I enable dnsmasq as my dhcp-server and dns and then I add a global-parameter option it seems like it gets added to /etc/dnsmasq.d/dnsmasq-dhcp-config.conf but it's commenteded out...
set service dhcp-server global-parameters address=/1.1.1.1/test.com
Yields:
admin@ubnt# cat dnsmasq-dhcp-config.conf
#
# autogenerated by /opt/vyatta/sbin/dnsmasq-dhcp-config.pl on Tue Aug 9 17:55:01 UTC 2016
#
dhcp-leasefile=/var/run/dnsmasq-dhcp.leases
# The following 1 lines were added as global-parameters in the CLI and
# have not been validated
#address=/1.1.1.1/test.com
....etc...
It looks like the script has it adding them commented...
foreach my $line (@global_params) {
my $decoded_line = replace_quot($line);
parse_custom_option_code($decoded_line);
$config_out .= "#$decoded_line\n";
}