$ perl -E 'say for "qwe", "qwe\n"'
qwe
qwe

##</code><code>##

$ perl -E 'say "|$_|" for "qwe", "qwe\n"'
|qwe|
|qwe
|

##</code><code>##

    my %big_image = map +(fc($_) => 1), $opt{big} ? @{$opt{big}} : ();
    for my $cross_file (@cross_files) {
        my $text  = textify($cross_file);
        my $class = 'svg_group';
        $class .= ' right' unless exists $big_image{fc $text};
    }

##</code><code>##

$ perl -E 'my %opt = ( big => [] ); say $opt{big}'
ARRAY(0x600003a90)

$ perl -E 'my %opt = ( big => [] ); say 0+@{$opt{big}}'
0