In addition to the excellent examples given:

# find "captured" in subroutine

use strict;
use File::Find;

my @dirs  = qw( /devel/dir1 /devel/dir2 );
my $exten = '.xml';
my @files = _get_files(\@dirs, $exten);

sub _get_files{
    my $dirs = shift;
    my $what = shift;
    my @files;
    my $want = sub {
        -f && /\Q$exten\E$/ && push @files, $File::Find::name
    };
    find($want, @{$dirs});
    @files
}
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