my @xml_files = $zip->membersMatching( '.*\.XML' );

  foreach (@xml_files) {
    my $xml = $_->xml();
    open my $xml_fh, '<', \$xml
            or die "Can't open scalar filehandle: $!";
[download]

What is the $_->xml() part? I know $_ is a member but I can't find anything about this xml method in Archive::Zip.