为什么我的Perl输出中会看到HASH(0xABCDEF)？

use strict;
use warnings;
use Data::Dumper;

my %hash = (
    key1 => 'value1',
    key2 => 'value2',
    key3 => 'value3',
);

print Dumper(\%hash);

$VAR1 = {
          'key3' => 'value3',
          'key2' => 'value2',
          'key1' => 'value1'
        };

use strict;
use warnings;

my %hash = (
    key1 => 'value1',
    key2 => 'value2',
    key3 => 'value3',
);

foreach my $key (keys %hash) {
    printf "%s => %s\n", $key, $hash{$key};
}

key1 => value1
key2 => value2
key3 => value3