Variables in YII2?

Question

Yii

Hello! I have a site on YII 2, I myself understand a little PHP, but my specialization is a bit off, and then this framework, so one question arose:
On the site, the variable <?php echo $usname; is displayed in certain places; ?> like this. But it is displayed strictly on certain pages. And I need to put it in layouts/main so that it is always visible.
To understand what the essence is, this is a brokerage admin panel, a framework on the UII, a minimum of changes. A person logs in> gets into a personal account. When you follow the links (choice of a broker, my accounts, etc), the inscription "username / balance" appears. But, because in the main layout, it is displayed in the content (page) variable, and I need to move it outside this div, where content is displayed. I can't figure out how to insert it into main.php so that it works and is displayed after login, regardless of the page.

Answer 1

https://github.com/yiisoft/yii2/blob/master/docs/g...
In the controller:
In layout:

<?= yii\widgets\Breadcrumbs::widget([
    'links' => isset($this->params['breadcrumbs']) ? $this->params['breadcrumbs'] : [],
]) ?>