You can define it as 
sub XORmask { '30d1c6615af8cfc9' }

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How did I get the magical value? By XORing the expected output with the $track. That's how XOR works.

#!/usr/bin/perl
use warnings;
use strict;

use MIME::Base64;

use constant XORmask => '30d1c6615af8cfc9';

my $id = 'Z0xcAVtKAwkDHVcKVF5TCQ';
my $track_decode = decode_base64($id);
print $track_decode ^ XORmask, "\n";

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($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,

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In reply to Re: Perl function equivalent to PHP xormask by choroba
in thread Perl function equivalent to PHP xormask by wubbaducki

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