Markup: templates/output/04-elements/forms/select.html
<div class="u-selectfield">
<select id="select1">
<option value="" disabled="disabled" selected="selected">Bitte wählen</option>
<option>Option One</option>
<option>Option Two</option>
<option>Option Three</option>
</select>
</div>
Source:
assets/sass/04-elements/_elements.forms.scss, line 565