I have a shell script code and I can't find the meaning of the $MPB that used there .

here is part of the code:
fprintf (script, "#-----------( Firestarter " VERSION ", Netfilter kernel subsystem in use )----------#\n");
	fprintf (script, "#                                                                             #\n");
	fprintf (script, "# This firewall was generated by Firestarter on %s              #\n", timestamp);
	fprintf (script, "# http://www.fs-security.com                                                  #\n");
	fprintf (script, "#                                                                             #\n");
	fprintf (script, "#-----------------------------------------------------------------------------#\n\n");
	/* Autoloading of netfilter modules must be done before chains are flushed.*/
    fprintf (script, "\n# --------( Initial Setup - Firewall Modules Autoloader )--------\n\n");

	fprintf (script, "# Remove ipchains module if found\n");
	fprintf (script, "$LSM | grep ipchains -q -s && $RMM ipchains\n\n");

	fprintf (script, "# Try to load every module we need\n");
	fprintf (script, "$MPB ip_tables 2> /dev/null\n");
	fprintf (script, "$MPB iptable_filter 2> /dev/null\n");
	fprintf (script, "$MPB ipt_state 2> /dev/null\n");		
	fprintf (script, "$MPB ip_conntrack 2> /dev/null\n");
	fprintf (script, "$MPB ip_conntrack_ftp 2> /dev/null\n");
	fprintf (script, "$MPB ip_conntrack_irc 2> /dev/null\n");
	fprintf (script, "$MPB ipt_REJECT 2> /dev/null\n");
	/* fprintf (script, "$MPB ipt_REDIRECT 2> /dev/null\n"); */
	fprintf (script, "$MPB ipt_TOS 2> /dev/null\n");
	fprintf (script, "$MPB ipt_MASQUERADE 2> /dev/null\n");
	fprintf (script, "$MPB ipt_LOG 2> /dev/null\n");
	fprintf (script, "$MPB iptable_mangle 2> /dev/null\n");
	fprintf (script, "$MPB ipt_ipv4optsstrip 2> /dev/null\n");
	fprintf (script, "if [ \"$NAT\" = \"on\" ]; then\n"
			 "	$MPB iptable_nat 2> /dev/null\n"
			 "	$MPB ip_nat_ftp 2> /dev/null\n"
			 "	$MPB ip_nat_irc 2> /dev/null\n"

	fprintf (script, "if [ \"EXT_PPP\" = \"on\" ]; then\n"
			 "	$MPB bsd_comp 2> /dev/null\n"
			 "	$MPB ppp_deflate 2> /dev/null\n"

   fprintf (script, "\n# --------( Initial Setup - Firewall Capabilities Check )--------\n\n");

	fprintf (script, "# Make sure the test chains does not exist\n");
	fprintf (script, "$IPT -F test 2> /dev/null\n"
			 "$IPT -X test 2> /dev/null\n"
			 "if [ \"$NAT\" = \"on\" ]; then\n"
			 "	$IPT -t nat -F test 2> /dev/null\n"
			 "	$IPT -t nat -X test 2> /dev/null\n"