<?php

    class Widget
    {
        public function getName()
        {
            return 'MyWidget';
        }
    }

    class WidgetExtensions
    {
        public static function getNameCapitalized(Widget $this)
        {
            return strtoupper($this->getName());
        }
    }

    register_extension_classes([
        WidgetExtensions::class => Widget::class,
    ]);

    (new Widget())->getNameCapitalized(); // MYWIDGET