Use yiisoft/yii2-bootstrap5 (ok)

https://github.com/yiisoft/yii2-bootstrap5

C:\xampp74\htdocs\oectest\views\country\index.php

<?php
use yii\bootstrap5\LinkPager;
// use yii\widgets\LinkPager;
use yii\helpers\Html;
?>
<h1>Countries</h1>
<ul>
<?php foreach ($countries as $country): ?>
  <li>
    <?=Html::encode("{$country->code} ({$country->name})")?>:
    <?=$country->population?>
  </li>
<?php endforeach;?>
</ul>
<?=LinkPager::widget(['pagination' => $pagination])?>