package Foo;

use 5.012;
use strict;
use warnings;

$Foo::V = "fred";

{
    local our $V = "waldo";

    say $V;
    sub bar {say $V};
    sub set_v {$V = shift};
}

package Baz;

Foo::bar;
Foo::set_v "fnord";
Foo::bar;

__END__

##</code><code>##

waldo
fred
fnord

##</code><code>##

waldo
waldo
fnord