/usr/share/perl5/Module/Build/Config.pm is in libmodule-build-perl 0.422000-1.
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 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59  | package Module::Build::Config;
use strict;
use warnings;
our $VERSION = '0.4220';
$VERSION = eval $VERSION;
use Config;
sub new {
  my ($pack, %args) = @_;
  return bless {
		stack => {},
		values => $args{values} || {},
	       }, $pack;
}
sub get {
  my ($self, $key) = @_;
  return $self->{values}{$key} if ref($self) && exists $self->{values}{$key};
  return $Config{$key};
}
sub set {
  my ($self, $key, $val) = @_;
  $self->{values}{$key} = $val;
}
sub push {
  my ($self, $key, $val) = @_;
  push @{$self->{stack}{$key}}, $self->{values}{$key}
    if exists $self->{values}{$key};
  $self->{values}{$key} = $val;
}
sub pop {
  my ($self, $key) = @_;
  my $val = delete $self->{values}{$key};
  if ( exists $self->{stack}{$key} ) {
    $self->{values}{$key} = pop @{$self->{stack}{$key}};
    delete $self->{stack}{$key} unless @{$self->{stack}{$key}};
  }
  return $val;
}
sub values_set {
  my $self = shift;
  return undef unless ref($self);
  return $self->{values};
}
sub all_config {
  my $self = shift;
  my $v = ref($self) ? $self->{values} : {};
  return {%Config, %$v};
}
1;
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