/usr/bin/mergebdf is in libbogl-dev 0.1.18-9ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | #!/usr/bin/perl -w
if ($#ARGV < 0) {
    die "Usage: mergebdf font1.bdf ... > newfont.bdf\n";
}
foreach $font (@ARGV) {
    open(F, "<$font") || die;
    for (;;) {
	while (defined($_ = <F>) && !/^STARTCHAR /) {
	    if (!$donehead) { print; }
	}
	if (!defined($_)) { last; }
	$donehead = 1;
	$c = $_;
	undef $e;
	while (($_ = <F>) !~ /^ENDCHAR/) {
	    if (/^ENCODING (\d+)$/) { $e = $1; }
	    $c .= $_;
	}
	$c .= $_;
	if (!$char{$e}) {
	    $char{$e} = 1;
	    print $c;
	}
    }
    close(F);
}
print "ENDFONT\n";
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