Sometimes you find crazy things

wat.php

<?php

$value = function (string $field, $default = null) use ($input_data, $notification, $user_setup) {
	$from_attr = substr($field, 0, 1) === '!';

	$val = $from_attr ? $user_setup->get(substr($field, 1), array_get($input_data, substr($field, 1), $default)) : $val = array_get($input_data, $field, $default);

	return htmlentities(substr($val, 0, 1) === '@' ? $notification->payload->get(substr($val, 1), $default) : $val);
};