Where does laravel gets the file name form a base64 decoded file

Question

i have an file encoded in base64 and when i decode it and dump with dd() in laravel and it shows the file name and type so i was wondering where laravel stores this since you cant get it from an base64 encoded file

My frontend javascript https://sourceb.in/ShOZspqBqA i know it does not look that nice

$files = json_decode($attributes['files']);
foreach ($files as $file) {
    $binary = base64_decode($file);
    dd($binary);
    $uuid = Str::uuid();
    Storage::disk('local')->put($uuid,  $binary);
}