baptisten-hohenacker_manual/user/plugins/losung/losung.php

<?php
namespace Grav\Plugin;

use Grav\Common\Plugin;
use RocketTheme\Toolbox\Event\Event;

/**
 * Class LosungPlugin
 * @package Grav\Plugin
 */
class LosungPlugin extends Plugin
{
    /**
     * @return array
     *
     * The getSubscribedEvents() gives the core a list of events
     *     that the plugin wants to listen to. The key of each
     *     array section is the event that the plugin listens to
     *     and the value (in the form of an array) contains the
     *     callable (or function) as well as the priority. The
     *     higher the number the higher the priority.
     */
    public static function getSubscribedEvents()
    {
	return [
            'onTwigExtensions' => ['onTwigExtensions', 0]
        ];
	/*return [
            'onPluginsInitialized' => ['onPluginsInitialized', 0]
        ];*/
    }
    /**
     * Initialize twig extension
     */
    public function onTwigExtensions()
    {
        require_once(__DIR__ . '/twig/LosungTwigExtension.php');
        $this->grav['twig']->twig->addExtension(new LosungTwigExtension());
    }
    /**
     * Initialize the plugin
     */
     
   /* public function onPluginsInitialized()
    {
        // Don't proceed if we are in the admin plugin
        if ($this->isAdmin()) {
            return;
        }

        // Enable the main event we are interested in
        $this->enable([
            'onPageContentRaw' => ['onPageContentRaw', 0]
        ]);
    }*/

    /**
     * Do some work for this event, full details of events can be found
     * on the learn site: http://learn.getgrav.org/plugins/event-hooks
     *
     * @param Event $e
     */
    /*public function onPageContentRaw(Event $e)
    {
        // Get a variable from the plugin configuration
        $text = $this->grav['config']->get('plugins.losung.text_var');

        // Get the current raw content
        $content = $e['page']->getRawContent();

        // Prepend the output with the custom text and set back on the page
        $e['page']->setRawContent($text . "\n\n" . $content);
    }*/
}