( excerpt from http://php
public function getDefaultProperties(): array<string, mixed>;
Gets default properties from a class (including inherited properties).
This method only works for static properties when used on internal classes. The default value of a static class property can not be tracked when using this method on user defined classes.
mixed- An array of default properties, with the key being the name of the property and the value being the default value of the property or NULL if the property doesn't have a default value. The function does not distinguish between static and non static properties and does not take visibility modifiers into account.