V8: how to get allowed file extensions for all users?

I need to check allowed file upload extensions:

$fs = FileSet::getGlobal();
$fp = $this->app->make(Checker::class, ['object' => $fs]);
$extensions = $fp->getAllowedFileExtensions(); // <- returns zero array
$allowed_extensions = implode(', ', $extensions);
$this->set('allowed_extensions', $allowed_extensions);

but looks like the above only works for an admin, but a normal registered user gets null.

How do I get the allowed extensions for all users even non-admin?

It’s weird. I logged in today as a non-admin user and the extensions are shown. I was testing my package yesterday adding and deleting users and entering/exiting them in/from groups. Without re-logging in. That might have caused the issue. Maybe sothing to do with permissions not updating without logging out and in. Looks like it’s working alright now.