Win8 Strawberry 5.8.9.5 (32)  Mon 09/13/2021  6:17:03
C:\@Work\Perl\monks
>perl -Mstrict -Mwarnings

use JSON;
use Data::Dump qw(dd);

# fixed and enhanced JSON string.
my $json_string = '
[
{
            "visio": {
            "Launch": false,
            "hide": {
                "iOS": true
                         },
            "appLinks": {
                "preview_sandbox_1_link": true,
                "fooble": false,
                "wibble": 42,
                "blarfl": "darble"
            }
        }

        }
    ]
';
# print "$json_string \n";  # for debug

my $arrayref = decode_json $json_string;
# dd $arrayref;  # for debug

# convenience variable.
my $appLinks_hashref = $arrayref->[0]{'visio'}{'appLinks'};

for my $appLink_key (keys %{ $appLinks_hashref }) {
    print "appLink key '$appLink_key' -> ";
    print "appLink value '$appLinks_hashref->{$appLink_key}' \n";
    }

^Z
appLink key 'wibble' -> appLink value '42'
appLink key 'blarfl' -> appLink value 'darble'
appLink key 'preview_sandbox_1_link' -> appLink value 'true'
appLink key 'fooble' -> appLink value 'false'