[kohadev-koha@kohadevbox:/home/vagrant/kohaclone (elastic_patron) ✹ ✭]% more Koha/SearchEngine.pm
package Koha::SearchEngine;
use constant {
    BIBLIOS_XXX => 'biblios'
};

1;
[kohadev-koha@kohadevbox:/home/vagrant/kohaclone (elastic_patron) ✹ ✭]% more xxx.pl
use Modern::Perl;
use Koha::SearchEngine;
my $xxx = $Koha::SearchEngine::BIBLIOS_INDEX;
say $xxx
[kohadev-koha@kohadevbox:/home/vagrant/kohaclone (elastic_patron) ✹ ✭]% perl xxx.pl
biblios
[kohadev-koha@kohadevbox:/home/vagrant/kohaclone (elastic_patron) ✹ ✭]% more Koha/SearchEngine.pm
package Koha::SearchEngine;
use constant {
    BIBLIOS_XXX => 'biblios'
};

1;
[kohadev-koha@kohadevbox:/home/vagrant/kohaclone (elastic_patron) ✹ ✭]% more xxx.pl
use Modern::Perl;
use Koha::SearchEngine;
my $xxx = $Koha::SearchEngine::BIBLIOS_XXX;
say $xxx
[kohadev-koha@kohadevbox:/home/vagrant/kohaclone (elastic_patron) ✹ ✭]% perl xxx.pl
Name "Koha::SearchEngine::BIBLIOS_XXX" used only once: possible typo at xxx.pl line 3.
Use of uninitialized value $xxx in say at xxx.pl line 4.