#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use XML::Twig;

my $header;
my $twig = 'XML::Twig'->new(
    twig_handlers => {
        h3 => sub { $header = $_->text; $_->purge; },
        'div[@class="event"]' => sub {
            say $header, "\t", $_->text;
            $_->purge;
        },
    },
);
$twig->parsefile('file.xml');
[download]

In bigger projects, you don't want to have a global header. Instead, you can create a new class that has two attributes, header and twig, which delegates all the XML related work to the latter and stores the headers in the former.

#!/usr/bin/perl
{   package XML::Twig::WithHeader;

    use feature qw{ say };

    use Moo;
    use XML::Twig;

    has _header => ( is => 'rw',   init_arg => undef );
    has _twig   => ( is => 'lazy', init_arg => undef );

    sub _build__twig {
        my ($self) = @_;
        my $twig = 'XML::Twig'->new(
            twig_handlers => {
                h3 => sub { $self->_header($_->text); $_->purge; },
                'div[@class="event"]' => sub {
                    say $self->_header, "\t", $_->text;
                    $_->purge;
                },
            },
        );
    }

    sub parse {
        my ($self, $file) = @_;
        $self->_twig->parsefile($file);
    }
}

my $twig = 'XML::Twig::WithHeader'->new;
$twig->parse('file.xml');
[download]

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]