/usr/lib/x86_64-linux-gnu/perl5/5.20/Params/ValidateXS.pm is in libparams-validate-perl 1.13-1+b1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | package Params::Validate;
$Params::Validate::VERSION = '1.13';
BEGIN { $ENV{PARAMS_VALIDATE_IMPLEMENTATION} = 'XS' }
use Params::Validate;
1;
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