use dokuwiki\Extension\ActionPlugin;
use dokuwiki\Extension\EventHandler;
use dokuwiki\Extension\Event;

class action_plugin_example extends ActionPlugin {
    public function register(EventHandler $controller) {
        $controller->register_hook('PLUGIN_POPULARITY_DATA_SETUP', 'AFTER', $this, 'usageData');
    }
    
    public function usageData(Event $event){
        $event->data['my_plugin_name'] = 'my usage data';
 
    /* or: 
        $event->data['my_plugin_name'] = [
            'k1' => 'v1', 
            'k2' => 'v2'
        ];
    */
    }
}