So, I should not be worried about clashing of variables with threads?

you said contents may not be used but threads will get their own "our" variable and threads can modify it, right?

I'm gonna await the sucker punch, but ostensibly: No, you shouldn't worry. Yes, threads can safely modify our variables:

A new thread will inherit a copy of any pre-existing global variable, but both it, and any other threads, may safely modify their copies of that variable without conflict. This may convince you.

#! perl -slw
use strict;
use threads;

my $tid = threads->tid;

our $fred = 12345;
print "$tid : $fred";

my $t = threads->create( sub{
    my $tid = threads->tid;
    our $fred;
    print "$tid : $fred";
    $fred = 54321;
    print "$tid : $fred";
} )->join;

print "$tid : $fred";
$fred = 'fred';
print "$tid : $fred";


__END__
C:\test>junk
0 : 12345
1 : 12345
1 : 54321
0 : 12345
0 : fred
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