I disagree with your hints. But, more importantly, they miss an important point:

#!/usr/bin/perl -w
use strict;

{
    package DEBUG;
    our $var = 'foo';
}

{
    package main;
    BEGIN { package Other; *main::var = \$DEBUG::var };
    #       ^^^^^^^^^^^^^   ^^^^^^
    print "Var is $var\n";
}
__END__
Var is foo
[download]

It doesn't actually have to be a third package, just not the destination package. So you could also use, for example:

    BEGIN { package DEBUG; no strict 'vars'; *main::var = \$var };
[download]