apdli-keycloak-theme/themes/base/admin/resources/partials/pagenotfound.html

<div id="content-area" class="col-sm-12" role="main">
    <div class="error-container">
        <h2 translate="page-not-found"></h2>
        <p class="instruction">{{:: 'page-not-found.instruction' | translate}}</p>
        <a href="#" class="link-right" translate="go-to-the-home-page"></a>
    </div>
</div>