2martens.de/_includes/sidebar/cv-pdf.html

<div class="card sidebar mb-3">
    <div class="card-body">
        <p class="card-text">
            <a class="btn btn-primary" href="{{ site.data.author.cv_pdf | relative_url }}">
                <span class="far fa-file-pdf"></span>&nbsp;Download CV
            </a>
        </p>
    </div>
</div>